Over 400 Hundred Verified  REVIEWS.IO (CLICK HERE)

2017 Trex® Transcend® PVC “CAPPED” decking with recycled wood & plastic core, which has been Corte-Cleaned® (ABOVE) Testimonial 4.7.2018


I have a Trex deck in a new construction home with 2 dogs. The grass just got installed last year along with the deck. This year the deck was so muddy and dirty I thought it would never look like it did last year. I followed the instructions exactly as it was stated and the deck looks brand new. I cannot believe the difference. I did have to rinse it very well to get all of the white residue off. I wish I took a before picture. The results are amazing. I will continue to use the product year after year.
N. Schmidt, OH. Verified on Reviews.IO


Corte*Clean® Instructional Video Click Here

Corte-Clean® customers can SAVE $2,310 +/- over 30 years!*

*See 2 composite manufacturer cleaning chemical recommendation price comparisons below!
BEFORE CORTE-CLEAN® – Mold stained, Grease & Oil, Rust, Weathered, Etc.

AFTER CORTE*CLEAN® – Same composite deck cleaned back to original color!

Why choose Corte*Clean® to CLEAN an expensive PLASTIC & WOOD COMPOSITE DECK?

CORTE*CLEAN® is for cleaning all common staining issues caused by mold & mildew, black spots, sap, grease, oil, barbecue, tannin, leaf, pine needle, chalk, berries, blood, sunscreen, olive oil, citronella candle oil, peanut butter, red wine, pet food & waste, hard water, grass, ground in dirt, clay, brick, flower pot, rust, grime, green slime & most other stains that are deep set or below the surface & can deeply root or saturate into the porous surfaces of most composites.



Corte-Clean® is designed to clean composites, especially those made from dirty recycled plastic, which can grow molds from within, & dirty recycled wood fibers, to clean what is known as “tannin bleeding”, or the food from which molds, mildews, lichens, mosses & algae can feed. Corte-Clean® then soaks into the pours of most composites & continues to clean any time it receives moisture, generally keeping composites clean for longer periods of time until thoroughly rinsed. Corte-Clean® does not have all the additional costs, environmental concerns, risks & time related to expensively purchasing & laboriously applying multiple other perceived in-expensive non-compatible cleaning chemical products, to clean specific stains.



You won’t need to purchase & use one or more specialty cleaning products for only cleaning common mold stains, especially those that contain sodium hypochlorite & are scientifically unproven for mold, or those “forget” products that claim to clean and/or prevent, but generally take weeks or months to work, if at all, especially if composites are located in routine moisture environments, where fungi rapidly grow & these products are generally rapidly rinsed, wasting time, labor & money. A 2nd product to clean tannin stains or corrosion stains from rust, which corrosive to structural metal decking hardware sodium hypochlorite & oxalic acid based cleaning products cause. A 3rd product for grease & oil; commonly under the barbecue. You won’t need to purchase & apply expensive products that claim to “Keep Mold From Coming Back” by sealing composites, which can exacerbate cleaning issues by sealing in fungi & stains, or expensive, laborious products to remove sealers when they begin to generally rapidly weather off/crack & look ugly. The information on this web site should be carefully considered. It will help guide you to why Corte-Clean® is the single cost-effective, eco-responsible, 100% biodegradable, non-corrosive to structural metal solution for cleaning & keeping long lasting composite decks, docks, & fences clean.



On Sale Now at CompositeDeckCleaner.com!

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Please READ if you wish to educate yourself regarding mold, the expense + numerous issues with most cleaning products & why Corte-Clean®?


Please review the entire Corte-Clean® website, Instructional Demo Video, & the Corte-Clean® Label Directions, to educate yourself regarding cleaning expensive, generally longer lasting composites, & keeping them clean. Not only does our small, one product, highly specialized family run American Made business want to make sure you get composites thoroughly Corte-Cleaned®, while providing quality customer service by representatives that have actually cleaned numerous composites, we want to make sure you thoroughly clean the underlying issues from which most composites are made that can feed fungi, in order for composites to generally stay clean for longer & for future cleanings to generally cost less time labor & money. Please read the well over 400 “Company Reviews” + over 200 “Product Reviews” for a total of over 600+ customer verified testimonials on Reviews.IO.


Lowe’s® ChoiceDek® made with recycled PE plastic & recycled oak hardwood.


No person wants to waste unnecessary time, labor & money cleaning anything, especially expensive composites that were generally believed to be “NO MAINTENANCE”, but commonly experience mold stains & difficult to remove grease, oil, rust & other common stains. Corte-Clean® has been proven for well over a decade by composite installers, retailers, distributors, manufacturers, maintenance professionals & most importantly; owners. Please call, if you have any questions after thoroughly reviewing the website.

Getting ready to Corte-Clean® Trex®, made from recycled PE plastic & recycled wood.


Cleaning wood & plastic porous composites & keeping them that way generally requires cleaning chemicals designed for this purpose. You wouldn’t use diesel fuel in a gas-powered motor unless you wanted to cause expensive problems, especially on a routine basis. The same is generally true when using cleaning products, not designed to clean specific stains from specific materials.

Trex® made from recycled PE plastic & wood when black mold stains first appear, after mold spores, in the air, land, receive moisture, germinate, hatch, grow hypha into a mycelium & form colonies.


Generally black & green appearing mold (sometimes spelled mould) is common growing into composites, while mildew, a very specific mold subspecies, is not. Mildew generally always appears white in color. Mildew is NOT generally the difficult to remove common pesky mold species, such as cladosporium or stachybotrys cartarum, commonly seen growing on building materials. Like mildew, algae, which generally only grow in water, such as a neglected swimming pool, isn’t common growing into composites, unless they are generally submerged.

ChoiceDek® Plus made from recycled PE plastic & recycled oak hardwood heavily colonized with common mold.


Common ugly looking, generally unhealthy, mold stains occur after mold spores, generally in the air, land on composite materials & receives moisture, germinate, grow hypha into a mycelium & become visable when it forms into a colony. Here is a map of where fungi is most likely to currently grow {blue is not likely, green is low, yellow is moderate, orange is high & red is very high} (click here). The most common mold stains generally start out looking like black oil drips, from a leaky motor, when first noticed, & appear about the size of a dime or nickel, but sometimes green molds grow into composites first. Composite owners often have no idea what it is?



Correct Deck® made from PP plastic & recycled wood heavily colonized with green mold, commonly confused with algae.


Chemical & composite manufacturers along with retailers have done a tremendous job of misleading composite owners into believing all molds are mildew, & green molds, mosses or lichens; are algae’s! They do this so they can recommend & sell products generally designed to clean only “mildew”, and/or “algae”, which are most commonly sodium hypochlorite or oxalic acid-based. Composite owners then purchase & use these products believing they are the right product to remediate or routinely clean & keep composites clean.

Correct® deck with common black mold stains. The left board has been Corte-Cleaned®


Most of the well-known, biggest branded composites, which are notorious for mold problems, especially those that are rapidly re-occurring are generally made with recycled Polyethylene (PE) plastics, that commonly came from plastic bags, shrink wrap, milk jugs, food packaging, etc. Unfortunately, the recycled plastic was not generally thoroughly cleaned of organic foods/debris/materials. These dirty plastics were likely going to feed fungi that consume rotting organic matter, where spores exist & they receives moisture, as this is what fungi does to feed & naturally recycle dead organic matter.

PE Milk jugs, shrink wrap, cheePE Milk jugs, shrink wrap, cheese wrappers, plastic bags & other dirty plastics commonly used to make composites. 


The most commonly recommended chemical, by composite manufacturers, under “Care & Cleaning”, for “Mold & Mildew” is “Sodium Hypochlorite”. Products containing this biocide are commonly recommend to be used on a routine “Spring and Fall” basis. The most commonly recommended brand name deck cleaning product, by at least two of the largest composite manufacturers was originally designed to only clean “mildew” from “wood”, as clearly stated on this products label directions. Most other deck cleaning products were originally designed to only clean “mildew” and/or “algae” from “wood”, while some additionally claim to clean only “vinyl“, a specific type of Polyvinyl Chloride (PVC) plastic. One composite manufacturer recommended sodium hypochlorite-based cleaning product  claims to clean only “non-porous” “vinyl” of “mildew”, then goes on to state “It is a violation of Federal law to use this product in a manner inconsistent with its labeling” even though the composite they manufactured was made of PE plastic & wood. These products should not be used to clean other types of plastic, such as PE or Polypropylene (PP)  of common black & green molds, which are not mildew, unless one generally wishes to ignore these products label directions.

Trex® where the most commonly recommended “sodium hypochlorite” based product, originally designed & intended to only clean “wood” of “mildew” was routinely used “Spring & Fall”, for years, until completely colonized with common black mold. Notice how the mold no longer spots, but has completely taken over the boards. Notice the red rust corrosion stains is around the fasteners! This is a worst-case scenario, especially since this deck was not properly installed, with proper gapping, in-between boards, to allow water to easily drain.


Could the use of products designed to clean only wood, and/or PVC vinyl plastic, damage PP or PE plastic polymers? Could the use of products designed to clean only wood, and/or vinyl, of mildew in an attempt to clean common black & green molds exacerbate the problem? Could the use of any sodium hypochlorite based product, to clean molds, including mildews, especially on a routine “Spring and Fall” basis, be the problem?


The Chlorine Bleach Scam!


Most people naively believe chlorine bleach or other sodium hypochlorite biocide based products, is how to KILL and/or sterilize to keep molds from coming back. They believe this even though the Occupational Safety & Health Administration, OSHA, (CLICK HERE), states {Under: “Use of Biocides”} “The use of a biocide, such as chlorine bleach, is not recommended as a routine practice during mold remediation”.  OSHA then states “When you use biocides as a disinfectant or a pesticide, or as a fungicide, you should use appropriate PPE, including respirators. Always, read and follow product label precautions. It is a violation of Federal (EPA) law to use a biocide in any manner inconsistent with its label direction.” Do you think it is ethical to ignore OSHA, especially as an employee of a retailer, composite or chemical manufacturer, when recommending, selling or using sodium hypochlorite based products for cleaning mold, from materials not stated on these products label directions, especially on a routine “Spring and Fall” basis?

Mold colonized Trex®, from the routine “Spring and Fall” use of “sodium hypochlorite” & partially Corte-Cleaned®. The deck is dry.


Sodium hypochlorite based products have been commonly routinely recommended even though a scientific study was conducted by Oregon State University (CLICK HERE) titled “Ability of bleach and other biocide treatments to remove and prevent mold…(2004, April)”, has proven the specific “biocide”, “sodium hypochlorite” to be ineffective in mold remediation, or the routine cleaning & keeping clean of mold, from the “wood”, of which most composites are partially made, by concluding “Increasing bleach concentrations from 2.5 up to 20 percent [sodium hypochlorite] solution had no effect on the appearance of the wood following the wash treatment, nor did such treatments completely eliminate fungi from the wood surface. The chemical mold prevention treatments tested were not effective in sterilizing the wood, nor did they improve the visual appearance.” Even if the “visual appearance” of the molds can no longer be seen, the molds will likely rapidly return if sodium hypochlorite has been used because as OSHA states; “In most cases, it is not possible or desirable to sterilize an area, as a background level of mold spores comparable to the level in outside air will persist”. “Outside air” is where most composites are located, as this is where most composite decking & fencing is designed & intended to be used. Why do composite & cleaning chemical manufacturers, along with retailers, choose to ignore this mold remediation science?

Completely mold colonized Trex®, from the routine “Spring and Fall” use of “sodium hypochlorite” & partially Corte-Cleaned®. The deck is wet, with water to magnify stains.


Composite & chemical manufacturers, along with retailers are interested in profits. As many have stated to us, they want the mold problem to appear to rapidly go away, to eliminate furious customers & expensive warranty claims while making a guaranteed routine profit. What could be more profitable than routinely recommending & selling highly profitable products, which almost guarantee the mold will rapidly returns sooner rather than later & the repeat sale of these products, which are generally available at most retailers & appear to initially rapidly bleach out mold & other cleaning issues, while having a low perceived price point & gennerally being accepted by the uneducated?

Mold infested TimberTech® Composite deck from years of routine sodium hypochlorite, till it had little if any chlorine bleaching effect with common black mold, resulting in the molds no longer spotting, but completely colonizing the entire composite boards. This is an example of a worst-case scenario which generally costs more time & money to thoroughly Corte-Clean®, as the mold has likely rooted throughout the plastic & is feeding off the wood fiber tannins!


Most composite owners trusted retailer, chemical & composite manufacturer cleaning chemical recommendations, for routinely cleaning common mold that contain “sodium hypochlorite” because it generally appears to bleach out the mold, the first several times it is routinely used. Most composite owners initially think these products initially “work great”, the first several times these products are routinely used! Don’t be fooled, the routine recommendation & use of sodium hypochlorite-based products almost always further exacerbates common mold problems, by making the molds more resistant to the chlorine in these products, every time they are routinely used. This is especially true if diluted or low sodium hypochlorite concentrations are initially routinely used. An example would be to start with those products that contain 3% sodium hypochlorite, as people generally start with the cheapest products they can find. They generally work their way up in price & chlorine strength as the lower priced, lower strength products have less & less of a bleaching effect. When these products generally fail in bleaching the mold, most then use a product that is a little more expensive & contains 5%+ sodium hypochlorite.  This generally leads to an absolute worst case scenario because this generally results in the molds no longer spotting but turning the entire composite boards black and/or green with mold. This is very much like routinely improperly using penicillin for common viral infections till it becomes ineffective. Eventually, the mold completely colonizes entire boards resulting in a worst-case scenario & common sodium hypochlorite-based products have little if any bleaching effect resulting in the mold no longer being bleached out. Perhaps you have experienced this?

Elk Cross Timbers® made from PE plastic & recycled wood, where the mold is no longer spotting but completely colonizing this composite deck! This is a result of the routine use of sodium hypochlorite-based product, originally designed to clean “wood” of “mildew”! Where the BBQ mat was blocking mold spores & moisture, notice no black stains.


The previous routine use of common low sodium hypochlorite concentration based products almost always results in sterilizing everything but the molds & other fungi, especially where spores exist in porous composite materials, or if a biofilm exists on non-porous materials, such as the newer PVC “capped” vinyl composites, while the water in these products, waters the fungi generally resulting in the rapid immediate re-growth, especially in sunny moist humid conditions. Semiannual routine “Spring and Fall” use of any sodium hypochlorite based products, at any sodium hypochlorite strength, generally results in visible mold stains never being fully bleached out, but only temporarily dulled, especially when composites are wet, with water, as water generally magnifies stains in composites.


Trex® completely colonized with black & green mold where sodium hypochlorite was routinely used for 15 years.


When the low concentration sodium hypochlorite-based products generally ultimately fail in routinely bleaching common molds, and/or result in rapidly returning funguses, customers then generally contact composite manufacturers to complain & file a warranty claim. Sometimes, the manufacturers send a representative to clean the composites, with an even higher concentration sodium hypochlorite-based specialty products, however, these products still aren’t even close to the “20%” sodium hypochlorite strength which OSU has proven to be scientifically ineffective for mold remediation. Composite manufacturers then generally recommend that owners routinely only use these more expensive highly profitable products moving forward. These products generally contain “sodium hypochlorite” & polluting “phosphates”, or “phosphoric acid” which can act like fertilizer for helping mold & other fungi rapidly grow, especially polluting algae’s, in water! Other composite manufacturers have chosen to recommend sodium hypochlorite-based products only available over the internet, with even greater sodium hypochlorite concentrations & more volatile surfactants, one of which has a short shelf life of approximately only one month.

Trex® where the “MUST be used within 30 days” product was recommended to be routinely used “Spring and Fall”, until it became mold colonized with common black & green molds. The owner that sent us this picture was routinely spending a fortune laboriously using this product, watching these fungi come back sooner & sooner while getting worse & worse with each application.


They profit, composite owners loose. Most notice that when sodium hypochlorite is routinely used, at any strength, the mold generally comes back sooner & sooner. Routinely using scientifically unproven sodium hypochlorite-based products for cleaning composites of common molds generally results in the needed to expensively purchase & laboriously routinely use these products more & more frequently, costing more & more time, labor & money.  Most don’t realize the use of these products are generally further exacerbating mold problems, by making the molds more resistant to higher concentrations of chlorine, while causing other irreversible damage to their expensive investment.

CORTE-CLEAN_CORRECT-DECK_BEFORE_MOLD-LICHEN-MOSSCorrect Deck® heavily colonized with black & green molds, previously only routinely cleaned with sodium hypochlorite, installed with stainless steel deck screws.


Composite manufacturers commonly use recycled wood in their products, as this is what makes them composite decks, not solid plastic decks. Some use hardwoods, such as “oak”, “maple”, etc., which are notorious for supporting common mold growth due to the structural cellulose being denser with tannins. Composite manufacturers didn’t generally clean the recycled wood fibers of tannins, to eliminate what is known as “tannin bleeding” in the composite decking industry, prior to making composite decking & fencing products. Failure to clean dirty recycled plastics & wood tannins, can result in molds growing from the dirty recycled plastic & feeding from the wood fiber tannins, when the fungi & composites receive moisture such as humidity, rain, morning dew or snow. This generally results in the perfect environment for these molds & other fungi to thrive, especially in humid warm sunlight! Composites made from virgin plastic & recycled wood, mold growth from within composite boards is less common, but still can occur if resilient  spores exist, before being extruded into composites. This explains why some composite owners have initially experienced molds growing “IN” only one composite board, & none surrounding it, while making others the perfect environment for funguses to spread.

Recycled hardwood oak or maple fibers commonly mixed with plastic to make composites.


Composite manufacturer extruders can’t generally get hot enough to kill or sterilize extremely resilient fungi spores. The dirty plastic & wood generally catch fire first. It is our understanding that heating the wood & plastic, in an attempt to sterilize these materials, to eliminate fungus problems from within, while extruding these materials into products,  has burned down at least one composite manufacturing plant.

Tannin bleeding from the virgin PE plastic & wood of which this partially Corte-Cleaned® TimberTech® composite deck is made. It generally takes two (2), or more, Corte-Clean® applications to eliminate tannin bleeding, from composites that haven’t been previously Corte-Cleaned, depending on the type of wood composites are made from. Hardwoods, such as oak, maple, etc. generally require more applications than softwoods, due to the wood being more dense with tannins, which can be more food for funguses to feed.


Sodium hypochlorite based products don’t generally clean the  wood, from which most composites are partially made, of tannins, to eliminate “tannin bleeding”. They generally chlorine bleach out the redwood, cedar, teak, mahogany, etc. tannin colors, or the natural beauty from wood while destroying the wood lignin, or natural glue that holds the cellulose together, which is why some sodium hypochlorite based products have specific dilution guides for wood or do not recommend the products they manufactur come into contact with wood at all. Wood deck owners generally wish to restore these beautiful tannin pigments, not chlorine bleach their color.

Corte-Clean® cleaning mold stains & tannins from the oak wood fiber & recycled PE plastic of which this Lowe’s® ChoiceDek® is made. Failure to thoroughly Corte-Clean® composites, to eliminate mold & other fungus stains, & tannin bleeding, generally results in mold stains re-occurring sooner, rather than later. Do not cut corners, by ignoring all Corte-Clean® product label directions, or you are likely wasting your time & money with this serious industry-wide known problem.


Once the wood has been chlorine bleached, chemical manufacturers & retailers generally recommend & sell a “wood brightener”, which contains “oxalic acid”, which at least one product claims to “Neutralize and brighten surfaces that have been stripped with corrosive strippers”, such as those products that contain sodium hypochlorite. Therefore, oxalic acid-based cleaning products that restore bleached tannin pigments, or brighten them, & do not remove them, to eliminate tannin bleeding, generally do the exact opposite of what is necessary to clean composites of the underlying issues which can feed fungi. Using an oxalic acid based product, should not be used in an attempt to clean composites of wood “tannin bleeding” unless one generally wishes to accomplish the exact opposite of what is generally necessary to keep composites clean.

Trex® growing other fungi within weeks of being cleaned with sodium hypochlorite & oxalic acid where the tannin bleeding issue was not properly cleaned.


Composite cleaning issues, specifically those caused by molds, generally due to neglect or improper cleaning chemical product recommendations, is a serious industry wide known problem. Unfortunately, many composite owners have experienced rapidly re-occurring mold & other fungi because of poor cleaning chemical recommendations & use, which has tarnished the overall reputation of the composite decking industry. Unfortunately, most continue to ignore these facts?

Corte-Clean® working to clean mold stains from this black mold stained Trex® deck (left 2 deck boards). Look carefully, you can still see Corte-Clean® turning dirty, discolored or yellow as it is cleaning the mold stains & tannins from the wood fibers that this composite deck is partially made.


The use of sodium hypochlorite generally does excessively chlorine bleach the color of almost all composites, especially when used in direct sunlight, when most people clean composites, because they were designed to only clean “wood” and/or “vinyl” PVC, not PP or PE plastic. Composites, especially those made from recycled PE plastics, which were generally colored after the plastic was made or recycled, generally bleach beyond what is disclosed under “weathering”, or bleaching/fading, as disclosed by some composite manufacturers, especially when using products that contain a higher concentration or percentage of sodium hypochlorite, undiluted, and/or volatile detergents known as surfactants, are used. This generally leads to the 2nd biggest complaint in the composite industry, excessive color fade by chlorine bleaching.



Corrosive to structural metal cleaning chemicals???!!!


Trex® where “sodium hypochlorite” was recommended to be routinely used, “Spring and Fall”, in their “Mold Technical Bulletin” until completely mold infested! Notice the black spots growing into mold colonies & the red rust corrosion bleeding from the screws fastening the composites to the substructure. What do you think this corrosive to structural metal cleaning chemical has done to the non-visible joist hangers, nails or screws under the decking?


There’s likely good reason USP® Connectors has disclosed the “causes of external attack by chemicals like chlorine bleach” and Simpson® Strong-Tie has disclosed the “corrosion risks” of “cleaning chemicals”! These are the two largest structural metal decking hardware manufacturers & commonly recommended in composite manufacturer “Installation Guides” and/or used in the construction of all decks! It is a good idea to check your specific decking hardware manufacturer literature or call & ask if it “Is it OK to use corrosive cleaning chemicals, that will likely come into contact with structural metal?” & “If the use of corrosive cleaning chemicals will void the manufacturer warranty of the structural metal decking hardware?”

A galvanized Simpson® Strong-Tie joist hanger & Swan® Stainless Steel composite deck screw commonly used in deck construction soaked in Corte-Clean® until all water evaporated. No Corrosion. Don’t try this with any sodium hypochlorite based product, as you will then understand the corrosion risks of this corrosive cleaning chemical.



There is likely good scientific reason related to corrosion to why one of the most well-known sodium hypochlorite-based cleaning products, “CLOROX® OUTDOOR BLEACH CLEANER”, has disclosed “DO NOT USE THIS PRODUCT IN FULL STRENGTH”, “Always dilute strictly in accordance with label directions” for “galvanized” “materials”, “Strength” “Low (Green)” “Dilution” “1:21” “6oz (3/4 cups) of product to 122oz (15 ¼ cups)” of water. This product label directions then go on to state “Prolonged contact with metal will cause pitting and discoloration.”, such as black or red rust stains in composites around these items! Most retailers, composite & chemical manufacturers have recommended & sold sodium hypochlorite-based products that are to be used at greater sodium hypochlorite concentrations. At least one product for cleaning decking label directions recommend their product be “applied at full strength”, which is a much greater than what CLOROX® discloses!

Corroded Joist hanger & nails!
Corroded galvanized nails almost always used with joist hangers in deck construction!


“Galvanized” “materials” are almost always used in the manufacturer of joist hangers & nails, to structurally support & hold together almost all composite decks, due to these items being generally recommended by composite deck manufacturers in “Installation Guides”, often in the same brochure as the “Composite Deck Care & Cleaning” literature. The rare exception is where more expensive stainless-steel joist hangers & fasteners have been used. Stainless-steel is commonly used to fasten composites to the structure under it, with screws, especially when hidden fastener systems are used. As GRK Fasteners® has stated “Chlorine-based bleaches and cleaners are not recommended for most deck fasteners, our Climatek coated products included. Our PHEinox stainless steel fasteners can handle these harsh chemicals much better, but the use of such chemicals are not recommended in the first place; they are harsh on the decks themselves and joist hangers and other such deck hardware.” While stainless steel is generally more resistant to corrosive cleaning products than galvanized metal, it is not immune to corrosion, as it too generally “pits”, resulting in the loss of structural value.

Corroded “pitted” stainless steel screw commonly used to attach composites to the structure underneath. It can be scary to see what screws pulled from composite decks look like, that have been routinely, Spring and Fall, cleaned with corrosive cleaning chemicals such as those that contain sodium hypochlorite or oxalic acid at the recommendation of retailers, composite or chemical manufacturers.



Oxalic Acid can be corrosive to structural metal decking hardware too!


“Oxalic acid” based products, known as “deck brighteners”, commonly recommended by composite manufacturers to “remove rust” and/or “tannin stains”, in addition to “mold and mildew”, as recommended by some composite manufacturers should ring a bell? They have chosen to recommend this corrosive to metal cleaning chemical even though at least one chemical manufacturer of this acid-based product states on its label directions “DO NOT USE ON” “METALS”, but claim their product is for “decking”, where structural metal decking hardware is generally used? You really should ask if the product(s) they recommend, manufacturer & sell are corrosive to structural metal & safe to clean a deck, before ever purchasing & using these products.

Corroded screws & nails commonly used by contractors & those cutting corners to foolishly save money on construction costs, then choose multiple perceived inexpensive corrosive cleaning chemicals to routinely clean their expensive otherwise longer lasting composite deck!
Corroded decking joist hanger & nails!!!

Irreversible corrosion to structural metal, caused by the recommendation & those profiting from corrosive composite deck cleaning chemicals products, especially when recommended be used on a routine “Spring and Fall” basis, can lead to extremely laborious & expensive early replacement when corrosion is noticed. Do you think retailers, chemical & composite manufacturers are going to pay to replace the irreversible corrosion damage they have caused by recommending and/or profiting from the sale & use of corrosive to metal decking hardware oxalic acid or sodium hypochlorite-based cleaning chemicals? Why any chemical manufacturer would produce corrosive to metal deck cleaners, or composite manufacturers would recommend multiple corrosive to metal deck cleaners, or retailers would sell corrosive to metal deck cleaners, especially when oxalic acid & sodium hypochlorite are non-compatible poisonous chemicals, especially with porous composites, makes no sense?

Corroded structural metal I-Beams under composite decking as recommended & sold by at least one major composite manufacturer who routinely recommends sodium hypochlorite & oxalic acid for routine “Spring and Fall” cleaning!


Failure to replace structural metal, when corrosion is noticed, can lead to structural failure, when generally under load from the increased weight of people! This is inexcusable, especially if people are injured or worse when it could have been totally avoided by retailers, composite & chemical manufacturers.  This is currently the #1 Ticking Time Bomb in the decking industry, most retailers, chemical & composite manufacturers & owners continue to ignore???!!!

Could the routine recommendation & use of sodium hypochlorite to clean mold from composite decking, corroded the bolts & joist hangers, like the above photo & lead to structural failure, that held the below ChoiceDek® to the header attaching it to the house? Why would any person or company ever even take the risk, when people could be injured or worse? Nothing could be more expensive!
We are seeing & hearing about more deck collapses with composites as the years go by. Faulty construction practices are likely sometimes to blame? Do you think the routine recommendation & use of corrosive to structural metal cleaning chemicals makes decks more or less likely to structurally fail? Ask yourself that question before ever using a corrosive to metal deck cleaning product!

WARNING! It is HIGHLY recommended that composite owners get their decks professionally inspected on a yearly routine basis, especially if they have noticed corrosion, sodium hypochlorite, oxalic acid or other corrosive cleaning chemicals have been used, salts have been used to melt ice or it is located in a corrosive environment, such as near the ocean! Nothing could be more expensive than a deck collapse where people are injured or worse!


Recommendation & Use of Multiple Non-Compatible Cleaning Chemicals can be DANGEROUS!


WARNING! Using multiple non-compatible cleaning chemicals, one after the other, to clean specific stains, from porous composites, which can soak into composites, can release poisonous toxic fumes, that are more poisonous than chlorine bleach alone!  DO NOT DO MIX CLEANING CHEMICALS!! POISONOUS TOXIC FUMES WILL VERY LIKELY RESULT FROM POROUS COMPOSITES. Read & follow any chemical cleaning products label directions, especially WARNINGS & DISCLOSURES!


Do you think using non-compatible chemicals, one after the other, to clean porous (soaks into) composites could release toxic poisonous gas? Commonly recommended dishwashing soaps, sodium hypochlorite, oxalic acid, oil stain removers, the “forget” products, sealers & most other chemical based products can & generally do release poisonous toxic fumes when used one after the another to clean or prevent porous composites of specific stains. Any person, especially composite manufacturer employees that have tested and/or used these chemicals in order to recommend them, would be recklessly foolish to not carefully read & follow any products label directions, or OSHA guidelines, especially when recommending specific chemicals and/or products to the uneducated general public, be used one after the other, for cleaning porous composites of specific stains!

ChoiceDek® Composite Post Cap – Before/black mold stains/cleaned w/only sodium hypochlorite & after Corte-Cleand®


Breathing sodium hypochlorite alone isn’t smart & why the “CLOROX® OUTDOOR BLEACH CLEANER” label directions state “Not recommended for persons with heart conditions or chronic respiratory problems such as asthma, emphysema or obstructive lung disease.”, hopefully, you haven’t experienced the toxic, poisonous outgassing when it is mixed with other commonly recommended chemicals, as we unfortunately have, when proving Corte*Clean® alongside multiple other cleaning products, for major composite manufacturers. The poison generally smells like burnt rubber or plastic, generally resulting in temporary loss of smell/taste & a terrible nauseating chemical headache, that can last for hours or days! Breathing this toxic gas can lead to long term debilitating health issues, which are obviously worse than breathing chlorine alone, especially with the young, the elderly, or those that suffer from breathing conditions; such as asthma, bronchitis or emphysema. “All known retailers & composite manufacturers have all been made well aware of these facts, since approximately 2006, but continue to ignore the risks they recommend to their customers & employees who routinely follow multiple cleaning chemical recommendations, to clean specific stains.

Trex® Before Black Mold Stained (left of picture) & After Corte-Clean® (right of picture).


Composite manufacturers generally start out by recommending a “soap”, in the form of a “dishwashing detergent” for cleaning “oil & grease” and/or “tannins” even though one of the largest dishwashing detergents label directions states “It is a Federal law violation to use this product in a manner inconsistent with its labeling” while stating it is for “general dishwashing”, to clean “dishware”, such as “dishes” of “greasy surfaces” including “kitchen surfaces” such as “countertops, stoves and related surfaces”, of “bacteria” such as “staph aureus, salmonella and E. coli” but nothing about wood & plastic composites of “oil & grease” or “tannins”? Two of the other largest dishwashing detergent label directions state, of which the first is recommended by brand name by at least one composite manufacturer states “DO NOT ADD BLEACH!”, while the other states “Do not use with chlorine bleach to avoid irritating fumes”, such as using a sodium hypochlorite based product after using these products to clean porous composites!  When this generally almost always fails in cleaning composites, composite manufacturers commonly recommend a “sodium hypochlorite” or chlorine “BLEACH” based product, against OSHA recommendations, to clean “mold & mildew” which at least one deck cleaning products label directions states “PRECAUTIONS: Do not mix with any other chemicals as hazardous fumes may result”. They state this because “soaps”, such as those commonly recommended “dishwashing detergent” products generally contain non-compatible chemicals such as ammonia!  There is a potentially deadly serious reason why OSHA states “Never mix chlorine bleach solution with other cleaning solutions or detergents that contain ammonia because this may produce highly toxic vapors and create a hazard to workers.” and “CLOROX® OUTDOOR BLEACH CLEANER”  label directions states “Do not mix with any other household chemicals including deck cleaners, wood bleaches, wood restorers, rust removers, wood or masonry finishes, toilet bowl cleaners, acids or products containing ammonia. To do this will release hazardous gases.” Composite manufacturers then generally recommend a “deck cleaner” known as a “Brightener” that “contain oxalic acid” for “rust stains” be used as a “rust remover”, when composite owners complain about visible rust stains the sodium hypochlorite has caused even though at least one of these products label directions state “Do not mix with any other products, especially those containing chlorine or bleach.”, such as any product that contains “sodium hypochlorite”! Composite manufacturers then generally recommend a specific brand of “oil stain remover” which states on its label directions “do not mix with other chemicals” & “let it dry from a liquid to a powder, and sweep it up.”, which generally never thoroughly cleans it from within the pours of most composites. Some then recommend a product designed to not be rinsed & state “Do not mix {this product} with detergents or other chemicals”, such as a “deck wash containing a detergent”, known as surfactants, commonly sold in all known “sodium hypochlorite” based products,  but sometimes they recommend this product be used first.



seems to be what


care about MOST!


Cleaning Chemical Product Price Comparisons…


What TWO (2) of the LARGEST Composite Brands Have Recommend For Cleaning…


Composite manufacturer brand #1 cleaning chemical recommends as of 8.20.2018…

Under this composite manufacturer “Composite Deck Care & Cleaning Guide” instructions for their newer PVC capped with recycled plastic & wood core composites, they recommend to use “soapy water” under “Dirt and Debris”, however, they don’t state what product to use? When we called, they recommended a specific brand of liquid dishwashing detergent, which products label directions states “DO NOT ADD BLEACH!” They then go on to recommend a “Brightener” that “contain oxalic acid” & state “Deck brighteners contain oxalic acid, which will remove tannins.” They then again recommend “soapy water” for “Oil/Grease/Food”. Then under the button “EARLY GENERATION PRODUCTS”, which means non-PVC caped recycled PE plastic & wood composites, it is stated under “Dirt and Debris” to “Clean deck to remove dirt and debris. Soap and water is all that is needed.” Under “Oil/Grease/Food” they then recommend an “OIL STAIN REMOVER” which states the “COVERAGE: Treats a stain 3 feet in diameter. Approximately 6 square feet” & states “let it dry from a liquid to a powder, and sweep it up.”, which likely doesn’t thoroughly remove this product from this companies porous composite materials & “do not mix with other chemicals.”, like the above recommended “soap” & “oxalic acid”! This oil stain remover costs $8.99 for 16 Fluid Ounces + $7.95 Standard Shipping, for a total of $16.94 directly from this companies website. However, you do notice they sell a “Composite Deck Spot Remover”, which contains “32 Fluid Ounces” & costs “$13.99” + “Standard shipping $7.95” for a total of $21.94. You order the composite manufacturer recommended product because it is less money, but wonder why the composite manufacturer would recommend a product for cleaning composites, when the chemical manufacturer makes a product specifically for cleaning composite decks? The product arrives! The product generally works & removes the oil & other stains. The only problem is you now need to buy enough to finish the rest of your 300 Sq. Ft. composite deck! 300 Sq. Ft – 6 Sq. Ft. results in you needing to purchase enough product for the rest of the 294 Sq. Ft., or 294 divided by 6 or for another 49 purchases of this product at $16.94 each, for a total cost of $830.06! Quickly, most decide that is too much money. You then remember the chemical manufacturer sells this product in larger quantities, so you go back to the website & look. 32oz costs $13.99 +7.99 shipping for a total of $21.98, the same price as this chemical manufacturer’s composite cleaner, 1 Gallon or 133.23oz which cleans approximately 49.96 Sq. Ft. & costs $45.99 + $10.95 standard shipping = $56.94! You will need 6 gallons to clean the average 300 Sq. Ft. composite deck, but when you order more than $100, shipping is FREE, so the total cost is $275.94! Most decide to look for something else, as this seems like a lot of money to only clean 300 Sq. Ft.! This composite manufacturer then states under “Mold and Mildew” that “Semi-annual (spring and fall) cleaning of your deck is important to prevent the build-up of pollen and other debris that can support the growth of mold. Refer to Mold Technical Bulletin for specific cleaning recommendations”. Most then click the “Mold Technical Bulletin” PDF link that states “How to remove Mold from” this companies “Composite & PVC Decking”, & states, “If mold colonies appear, clean the deck with a commercial deck wash containing a detergent and sodium hypochlorite, commonly known as bleach. This chemical will remove the mold” & “If the deck has not been cleaned regularly, it may require several treatments with the deck wash to completely remove all mold colonies.” They then recommend two (2) specific sodium hypochlorite-based products, the first of which doesn’t appear to have been originally designed to clean composites of common black mold, as this products label directions from its website states “Before” with an artist rendering of a dirty weathered grey black mold stained wood deck, & “After” photo shows an artist rendering of cleaned wood deck. This product then describes itself as a “DECK CLEANER”, “FOR CLEANING PRIOR TO STAINING” which claims it “Removes dirt & mildew stains”, from “wood and other surfaces”, then states, “It cleans stains caused by mildew, dirt, algae and mold”, & that this product “CLEANS UP TO 300 SQ. FT”. On the back of this products label directions, it states “Use on decks, wood siding, shakes, shingles, and fences. Also recommended for use on concrete, brick, stucco, tile, and vinyl. Use of this product may return the original green color to pressure treated wood. Application of this product may cause a fuzzy appearance to wood previously damaged by pressure washing or excessive weathering. Application to new wood or newly sealed wood may cause spotting and discoloration. May cause redwood to darken”. Vinyl is PVC plastic, not the “EARLY GENERATION PRODUCTS” PE recycled plastic known for mold problems with this composite manufacturer’s non-capped products. Then this product states “PRECAUTIONS: Do not mix with any other chemicals as hazardous fumes may result”. Such as the “soap”, “oxalic acid” or “oil stain remover”! This product then recommends being “applied at full strength” while containing “sodium hypochlorite” at “% ≥5.0 – ≤10” according to this products Safety Data Sheet. Newer packaging states “removes dirt, mold & mildew stains” with a sticker and/or new label addition that now states “ALSO FOR CONCRETE & COMPOSITE”. Keep in mind, the only “COMPOSITE” mentioned on this products label directions are “VINYL” or PVC, not the “EARLY GENERATION” PE plastic “PRODUCTS” for which this composite manufacturer is recommending this product be used, likely resulting in why this composite manufacturer has so many upset customers with excessive color fade who use this recommended product against its label direction?  This product generally retails from a home improvement warehouse for $9.98 + tax per 128 oz. or 1 gallon. The 2nd recommended “Mold and Mildew” product this composite manufacturer recommends is only available over the internet through the chemical manufacturer website. The “Description” on this products website then states “Composite Deck Cleaner & Enhancer is a heavy duty, mildly alkaline chlorinated mold and mildew remover/cleaner designed specifically for composite deck cleaning.” They claim their products “chemicals take care of your most stubborn mold, mildew and soil build up” while it “MUST be used within 30 days”. It then states “Each bottle should cover the entire process for 100 square feet of decking” & “Do not mix the deck cleaner chemicals with any other chemical as hazardous fumes may result”, like the recommended “soap”, “oxalic acid” or “oil stain remover”! This product then states “DO NOT DILUTE WITH WATER”. This product costs $19.98 + shipping! The average 300 Sq. Ft. composite deck will need 3 gallons or $59.94 + $40.37 (shipping to our zip code 94925, shipping may be less or more for you?) for a grand total of $100.31! The 3rd product this company recommends in their “Mold Technical Bulletin” claims on its website that it is “oxalic acid based liquid cleaner, brightener and stain remover”, “works best on natural wood or hard to clean surfaces such as concrete.”, “CLEANS & BRIGHTENS weathered gray wood surfaces”, “REMOVES STAINS associated with MOLD & MILDEW from wood and masonry” & “REMOVES TANNIN STAINS from bleeding woods such as cedar”. This products label directions state that it is a “BRIGHTENER STAIN REMOVER” for “WOOD · COMPOSITE DECKING · MASONRY” for cleaning “DIRT · MOLD · MILDEW RUST & TANNIN SURFACE STAINS”. This product claims it “MAKES UP TO 8 GALLONS”. You then click on the PDF “Spec Sheet” button & it states “removes dirt and stains caused by mildew and tannins”, then states, that this product “cleans and brightens weather-beaten wood” & that it is “Safe for use on” this specific composite manufacturer’s composite decking products, “and other plastic/wood composite surfaces” while claiming “1 gallon concentrate (makes up to 5 gallons)” [thought it made “8”?] and that the “COVERAGE” is “Up to 2,500 sq. ft. per gallon with a five to one water dilution”.  The label directions then state “if spraying, use NIOSH approved respirator”. Under “SUGGESTED APPLICATIONS” this product states “Remove mildew and clear finishes to restore wood to its original look”, “Neutralize and brighten surfaces that have been stripped with corrosive strippers”, then, that it will “Remove tannin stains from bleeding wood, such as cedar and redwood”, & “Ideal for cleaning and brightening most exterior surfaces, especially outdoor wood furniture, fences, decks and docks, including” this specific composite manufacturers products “and all other plastic/wood composite decking materials”, “DO NOT USE ON” “METALS”, & “Do not mix with any other products, especially those containing chlorine or bleach.”, Like the “soap”, “oil stain remover” or two “sodium hypochlorite” based products! This product costs $24.98 + $4.99 shipping for a total of $29.97 from its website. In summary, you’ll likely spend approximately $3 on “soap”, then $21.94 on the “OIL STAIN REMOVER”, then another $9.98 on 1st sodium hypochlorite product for the first “Mold” cleaning,  another $9.98 for the second “Semi-annual (spring and fall)” routine “Mold” cleaning, & $29.97 for the “brightener” that contains “oxalic acid” for a conservative total first year estimated cost of $74.87, on this composite manufacturer’s recommended cleaning products! You’ll likely then quickly discover why the 2nd “Mold and Mildew” product is recommended, when the 1st product originally designed to clean “wood” of “mildew” no longer bleaches out the common black molds, generally exacerbating the problem. Then, with routine “Spring and Fall” use, you will likely experience the molds rapidly returning or never really go away, especially when the deck is wet, with water, as water generally magnifies mold stains on this composite manufacturer’s products. When this generally occurs, this composite manufacturer then commonly recommends the purchase & use of the 2nd, more expensive, “Mold and Mildew” product, for your “Semi-annual (spring and fall)” routine cleaning thereafter. Molds & other fungi then generally begin to rapidly return more often, resulting in the need to purchase & using this expensive product more often than “Semi-annual (spring and fall)”? This 2nd “Mold and Mildew” recommended product will cost $100.31, from their website for the average 300 Sq. Ft. deck. Plus, you’ll generally need to pay another $16.94 for the “OIL STAIN REMOVER” to remove the oil stains from generally only under the barbecue, for a 2nd current yearly total cost of $117.25, but fortunately, you may have some leftover “oxalic acid” based product? By year 10 you will likely have conservatively spent $1,170.12+ following this composite manufacturer cleaning chemical recommendations. Now factor in the time, labor & other risks of using multiple, generally, non-compatible, corrosive to metal cleaning chemicals, which can result in premature expensive early replacement or potential structural failure! Please do your own diligence, as it would likely only cost you $39.99 for a single 2000A bag of Corte-Clean®, to initially clean this 300 Sq. Ft. composite deck, when stains were first noticed! Then to maintains this same deck’s clean appearance, on a “Semi-annual (spring and fall) cleaning of your deck is important to prevent the build-up of pollen and other debris that can support the growth of mold.”, owners of this manufacturer’s composites should be using up to ½ the Corte-Clean®, when using it at the “routine cleaning” strength, or spending up to ½ the money , thereafter. Many of this composite manufacturer composite deck owners use less & less Corte-Clean®, diluting it further, for the proactive cleanings & notice their composites generally staying clean for longer & longer, while spending less & less money! After 10 years, to keep this average 300 Sq. Ft. of this composite manufacturers composite decking clean, with Corte-Clean®, it currently costs $399.90 +/-, but should ultimately cost less & less as you fine-tune how little product you can proactively use to keep to keep this composite manufacturer product’s clean, which makes it even more environmentally responsible. $1,170.12 – $399.90 = $771.12!

A conservative approximate savings of $771.12 over 10 years for cleaning every 300 Sq. Ft.!

*Pricing was established on 8.20.2018 for all cleaning products from these products websites or retailers that sell them.
** You may spend more or less money keeping composites clean?


Composite manufacturer brand #2 cleaning chemical recommendations as of 8.20.2018…

This composite manufacturer states under “Care & Cleaning” that this companies composites have “Simple, Easy Cleaning & Maintenance Instructions”? Their website then states ” Our new embossed texture not only looks like natural wood grain, but it is also easy to clean. Our decks do not require painting, sealing or staining. So, don’t be afraid of messy barbecues. Ketchup and mustard spills just wipe away. Simply perform periodic cleaning with soap, hot water and a soft bristle brush. The best time to clean is after installation and semi-annually (spring and fall) to remove any debris”. They recommend three (3) “suggested cleaners for periodic maintenance”. You click on the link for the first product, which brings you to this product’s home page, where you see a button that says “Select your surface” and has pictures of brick/wood & what appears to be a roof & stucco siding and a button that states “Learn More”. You click the link & it brings you to a “PRODUCT PICKER” page. You scroll down & see every possible building material but a wood & plastic composite deck? So you click on the button with what appears to be an artist rendering of wood boards & states “DECKS”, as this seems logical? You click on the first product that states “32 oz. House and Deck Concentrate with Hose End Sprayer – treats approx. 600 Sq. Ft.” The products label directions states “REMOVES AND PREVENTS STAINS CAUSED BY MOLD, MILDEW, MOSS, ALGAE & LICHEN”, then states, “Do not mix {this product} with detergents or other chemicals” & “treats from 400 Sq. Ft. to 600 Ft.” & has a picture of wood & states “DECKS/FENCES” but states nothing about composite decking? This product costs $27.95. You hit the back button, click the button for the larger container, which claims this product “coverage 600- 1000 SQ. FT.”, as this product appears to be more of a value, as it states “Economical – makes up to 5 gallons” so you click the “BUY NOW” button. The product costs “$29.95” + “Flat Rate Shipping” of “$9.00” for a total of “$38.95”. You order it, it shows up, you follow its label directions, which state, “Do not mix {this product} with detergents or other chemicals”, spray it on your composite deck, don’t rinse it, & presto; generally nothing? You go back to this products website & it states under the “Results, Time & Application” button, “BLACK STAINS: Removed in 1-6 weeks from non-roof surfaces”. You patiently wait for this product to clean your half plastic composite deck of only these fungi stains, but it has likely rained, rinsing this product, generally preventing it from working, wasting your time & money? Unfortunately, after weeks, it generally still looks like it has measles, with black and/or green mold stains, with plenty of grease & oil stains, especially under/around the barbecue & table, sunscreen, from where someone sloppily applied it, stains around the flower pots & rust stains from metal, such as patio furniture or a BBQ. Those that see the deck begin to complain about it’s nasty looking condition. You go back to this composite manufacturer’s website, click on the next button, which recommends a 2nd product, which takes you to a specific store’s website. The product states it is an “OIL STAIN REMOVER”, which claims the “COVERAGE: Treats a stain 3 feet in diameter. Approximately 6 square feet” & states “do not mix with other chemicals.” & “let it dry from a liquid to a powder, and sweep it up. This 2nd product costs $14.98 from this specific retailer, which then stated that this product was “Unavailable for Pickup” from our local store. We then searched for the product online, find its website & notice this product costs “$8.99” for “16 Fluid Ounces” + “$7.95 Standard Shipping”, for a total of $16.94 directly from this company, so you order it from the less expensive retailer, because, under the barbecue has plenty of oil stains that the first product wasn’t designed to clean. However, you do notice they sell a “Composite Deck Spot Remover”, which contains “32 Fluid Ounces” & costs “$13.99” + “Standard shipping $7.95” for a total of $21.94. You order the 1st product because it is recommended by the composite manufacturer & is less money, but wonder why the composite manufacturer would recommend a product for cleaning composites when the chemical manufacturer that makes a product specifically for composite decks? The product arrives, you worry about ignoring the 1st products disclosure related to mixing chemicals! You then, thoroughly rinse the 1st product to make sure you don’t accidentally mix these 2 non-compatible chemicals in this porous material, guaranteeing the first won’t work, in case the rain hadn’t already, & apply the 2nd product by following its label directions. The product works & removes the oil stains. The only problem is you now need to buy enough to finish the rest of your 300 Sq. Ft. composite deck! 300 Sq. Ft – 6 Sq. Ft. results in you needing enough product for the rest of the 294 Sq. Ft., or 294 divided by 6 or for another 49 purchases of this product at $21.94 each, for a total cost of $1075.06! Quickly, you decide that is too much money. You then remember the chemical manufacturer sells this product in larger quantities, so you go back to the website & look. “32oz” costs “$13.99” + “$7.99 standard shipping” and is approximately 49.96 Sq. Ft. & costs “$45.99” + “$10.95 standard shipping” = $56.94! You will need 6 gallons to clean the average 300 Sq. Ft. composite deck, but when you order more than $100, Shipping is FREE, so the total cost is $275.94! Most decide to look for something else, as this seems like a lot of money to only clean 300 Sq. Ft.! You click the next “Premium Deck Cleaner” button on this composite manufacturer’s website, for the 3rd recommended product, which again takes you to a specific retailers website, which again states “This item is no longer available {at this retailer}.com.”, but has an artist rendering pictures of what appears to be a dirty weathered grey black mold stained wood deck & states “Before”. The “After” photo shows a cleaned “wood” deck. This product then describes itself as a “DECK CLEANER”, “FOR CLEANING PRIOR TO STAINING” which claims it “Removes dirt & mildew stains” from “wood and other surfaces”, then states, “It cleans stains caused by mildew, dirt, algae and mold” & that this product “CLEANS UP TO 300 SQ. FT”. On the back of this products label directions, it states “Use on decks, wood siding, shakes, shingles, and fences. Also recommended for use on concrete, brick, stucco, tile, and vinyl. Use of this product may return the original green color to pressure treated wood. Application of this product may cause a fuzzy appearance to wood previously damaged by pressure washing or excessive weathering. Application to new wood or newly sealed wood may cause spotting and discoloration. May cause redwood to darken”. Then this product states “PRECAUTIONS: Do not mix with any other chemicals as hazardous fumes may result”, such as the “soap”, the 1st product or the “oil stain remover”! This product’s label directions recommend it be “applied at full strength” while containing “sodium hypochlorite” at “% ≥5.0 – ≤10” according to this products Safety Data Sheet. Newer packaging states “removes dirt, mold & mildew stains” with a sticker and/or new label addition that now states “ALSO FOR CONCRETE & COMPOSITE”. Keep in mind, the only “COMPOSITE” mentioned on this products label directions is “VINYL” or PVC plastic, not the PE plastic for which this composite manufacturer is recommending this product be used, likely resulting in why so many customers experience excessive color fade, for those who use this recommended product against its label direction? This product generally retails from a home improvement warehouse for $9.98 + tax per 128 oz. or 1 gallon. Then this composite manufacturer recommends, under “Oil and Grease Stains (including lotions and candle wax)” “Household degreasing agents, such as {a specific brand of} dishwashing detergent, should be used to remove the oil and grease stain as soon as the stain is noticed.” This product generally retails for approximately $3 but clearly states “DO NOT ADD BLEACH!”, such as the previous chlorine “bleach” sodium hypochlorite based recommended product. Then this composite manufacturer recommends under “Below are suggested recommendations for specific cleaning issues:”, for “Water Spots”, to “use a deck brightener containing oxalic acid”. We called this composite manufacturer & they recommended a specific product, as this product is manufactured by the same company that manufacturers the other sodium hypochlorite-bleach based “Premium Deck Cleaner” product. This product claims to be a “GENTLE CLEANER FOR: PREVIOUSLY STAINED WOOD + BARE CEDAR & REDWOOD” to be used as a “DECK BRIGHTENER & WASH”, then states “CLEANS, BRIGHTENS & REMOVES MOLD & MILDEW STAINS”, “Excellent for rust & tannin stains” & “GENERALLY WASHES AWAY DIRT FROM PREVIOUSLY STAINED SURFACES”. This products Safety Data Sheet states it contains “Ethanedioic acid, hydrate”, commonly known as oxalic acid! Under “Incompatible materials” on this products label directions, this product states “oxidizing agents”, such as “sodium hypochlorite”, as sold in the other recommended, “Premium Deck Cleaner”, “wood” product for “mildew”! This is a sneaky way of disclosing not to mix these two non-compatible cleaning chemical products. This product retails from a box store for $9.98 + tax per 128 oz. or 1 gallon. Then under “Mold”, this composite manufacturer states “Based on our testing the most effective cleaner for quickly removing mold stains is” the sodium hypochlorite-based product. They then state “a bleach-based cleaner may temporarily lighten the surface appearance”. Then they go on to state “After cleaning, for long lasting results”, use the first recommended above product (above) “as an inhibitor”. They then go on to state the first product “can also be used as a cleaner in situations where instant results are not needed” & “Please refer to Mold and Mildew Cleaning for more information on mold removal.” You click on the link & a PDF opens for “MOLD & MILDEW” for “SUGGESTED CLEANERS” which have links to the 1st & 3rd products. For the 3rd product it then states “Contains bleach for Instant Results*” & “*Most cleaners contain Sodium Hypochlorite (commonly known as bleach). Any cleaner containing bleach may lighten surface wood fibers of the product while removing mold stains.” Back to the composite manufacturer “suggested recommendations” under “Rust stains / stubborn spots” they state “A cleaner containing oxalic acid, commonly known as deck brighteners, can be used to remove these stains.” Then this composite manufacturer states “For additional cleaning solutions, please visit the links below.” The “Tannin Instructions” PDF link then states; for “TANNIN, WATER OR RUST STAINS” & discloses “Lower-quality steel fasteners or electroplated screws are not recommended as they may not last as long as the deck boards and they can also create temporary stains your deck. On newly installed decks, runoff from metal objects, such as lawn furniture or decorative iron railings can create some temporary staining as well. These rust stains can also be easily removed with the use of a deck cleaner containing phosphoric or oxalic acid (ingredients will be listed on the front label or on the label on the back of the container).**Follow all package directions for proper usage, safety precautions and disposal. In some cases, more stubborn stains will require reapplying cleaners until the desired level of cleanliness is achieved. At times, brushing the deck with a hard bristle brush may be necessary to remove any stubborn staining. Excessive scrubbing may cause a temporary scuff mark that will weather away. Always test chosen cleaners in a small inconspicuous area of your deck for approved results. Never mix any other cleaners (ammonia, phosphoric acid, etc.) with bleach.” This composite manufacturer wants you to buy & use the first product for $38.95, the 2nd product for $16.94, the 3rd product for $9.98 + tax, the 4th product for call it $3 + tax, & the 5th product for $9.98 + tax. Without the tax, that’s $78.85 & assuming these products all clean 300 Sq. Ft., which they don’t. This total yearly price does not contain the “phosphoric acid” they recommend? You’ll have to purchase & laboriously use most these products as this manufacturer suggests at least twice per year “semi-annually (spring and fall)” to keep this decking clean so that would cost $38.95+$9.98 +$16.94 + $3+ $9.98 for a total initial purchase price cost of $162.70! You likely only need to purchase the $38.95 product once yearly, due to the coverage this product claims to clean & keep clean, so we deducted it from the 2nd yearly “Spring & Fall” recommended cleaning chemicals cost of this composite manufacturer or $162.70 – 38.95 equals a total yearly cost of $123.75 to purchase all this composite manufacturer’s recommended cleaning chemicals! If you follow this composite manufacturer’s cleaning chemical recommendations for 10 years, that equals $1,237.50! Now factor in the time, labor & other risks & replacement costs! Please do your own due diligence, as it would likely only cost you $39.99 in for Corte*Clean® to initially clean this 300 Sq. Ft. of this companie’s composite decking, when stains were first noticed, of all common stains! Then to maintains this same composite deck’s clean appearance, owners of this manufacturers composites should be using approximately up to ½ the Corte*Clean®, when using it at the “routine cleaning” strength, or spending up to ½ the money. Many of this composite manufacturer’s composite product owners use less & less Corte-Clean®, diluting it further, for proactive routine cleanings & notice their composite deck staying clean for longer & longer, while generally spending less & less money without the risks of using multiple cleaning chemicals! After 10 years, to keep this average 300 Sq. Ft. composite deck clean, with Corte-Clean®, is currently approximately $399.90 +/-, but should ultimately cost less & less as you fine-tune how little product you can proactively use to keep it clean, which makes it even more environmentally responsible. $1,237.50 – $399.90 = $837.60!

A conservative approximate savings of currently $837.60 over 10 years for cleaning every 300 Sq. Ft.!

*Pricing was established on 8.20.2018 for all cleaning products from these products websites or retailers that sell them.
** You may spend more or less money keeping composites clean?
***If any Corte-Clean® customer can find a flaw in our 2 price comparisons, please let us know. We will discount Corte-Clean® for you if verified. We became thoroughly confused & overwhelmed with these 2 companies cleaning product recommendations! To the best of our knowledge, they are correct?

Please do your own diligence for your specific composite manufacturer cleaning chemical recommendations!

Black & Green Mold stained PP based Correct Deck® (left) & Corte-Cleaned® (right).


1st add up the cost of all the cleaning chemicals composite manufacturers recommend to clean 300 square feet, the average composite deck size. Then factor in the time or labor costs to use them. Are the cleaning chemicals compatible, especially when cleaning porous composites, where they are generally mixed, resulting in toxic poisonous outgassing? If routinely used, will they keep your composites clean for longer & longer, for less money or shorter & shorter while costing more money? Will you be paying to replace corroded structural metal caused by these chemicals? Will they weather/bleach/fade composites beyond what most manufacturers disclose, resulting in the need to expensively re-color composites on a routine basis?

Corte Clean® working (left of photo) to clean common black mold stained Trex® made from recycled PE plastic & wood.


When we bring up the science, outrageous costs, time, labor & risks or dangers of specifically the multiple cleaning chemicals composite manufacturers continue to recommend, some composite manufacturers have chosen to no longer recommend our proven product in retaliation. A former CEO of one of the largest publicly traded composite manufacturers told us “his mother had been using chlorine bleach for decades to kill mold, so he was recommending it to his customers” even though he was shown the facts? Perhaps your specific composite manufacturer, that recommends the CHLORINE BLEACH SCAM and multiple other expensive non-compatible cleaning products will listen to you as it relates to these facts?


Why do you think composite manufacturers recommend multiple perceived inexpensive cleaning chemicals, which ultimately cost more money?


Could it be the routine financial kickbacks, for recommending multiple, perceived inexpensive, but ultimately more profitable cleaning chemicals, especially those that are sodium hypochlorite based & scientifically un-proven for black mold, generally resulting in its rapid return, & the need for composite owners to rapidly re-purchase/laboriously re-use & increased profits, outweighs customer safety & overall satisfaction with the composite decking industry & reputation? We’d almost think its funny what composite manufacturers routinely recommend for cleaning if it wasn’t so expensive, potentially dangerous, environmentally irresponsible & resulted in so many furious composite owners! Any person who can read any products label directions should & would know better than to recommend multiple non-compatible chemicals! From the looks of it, especially with what it has already cost composite manufacturers & owners, you’d think they let untrained, uneducated individuals recommend cleaning chemicals, especially when it comes to molds, which has plagued the composite industry, as it doesn’t take a genius to do the basic research to understand what should never be used, especially to clean longer lasting porous composite decking with structural metal!





Corte-Clean® does NOT contain sodium hypochlorite, the active biocide in Chlorine Bleach!


Corte-Clean® is a single composite owner proven product, to clean composites, of all common stains, not just those caused by molds, in a far safer, more cost-effective & environmentally responsible, biodegradable manner without corroding structural metal decking hardware. More importantly, Corte-Clean® is proven in keeping composites clean, at generally a much lower cost, for generally longer & longer periods of time when properly proactively used, especially if proactively used more often than not the first several years. Corte-Clean® has existed for over a decade because of this fact. Please do your own diligence by reading our customers verified testimonials on Reviews.IO, if you haven’t already!

Corte-Clean® BEFORE & AFTER artist rendering.


Corte, LLC provides a GUARANTEE & LIMITED WARRANTY along with quality customer service, by people who have actually cleaned numerous composites with Corte-Clean®, & just about everything else before discovering Corte-Clean®, for major composite distributors & manufacturers! Corte-Clean® was originally developed by a chemical manufacturer owner, whose business was established in 1960 & a chemical engineer professor for a major university. They specialized in automated car wash cleaners & cleaners in the food industry, specifically with wine production equipment & mold remediation. Corte-Clean® was developed to clean his personal Trex® deck & dock, in the San Francisco Bay Area, then tested by composite distributors & manufacturers until perfected. Corte LLC was founded in 2006 to bring the proven product to market when composite owners began calling back looking to get more product to keep their composites clean, especially after generally trying multiple other products. Corte LLC wants every customer to be satisfied with the results of Corte-Clean®, so they can generally spend more time enjoying their clean composites, & less time & money cleaning them & keeping them clean.

If you are one of our many new customers, that has neglected, improperly previously cleaned, only power washed or used sodium hypochlorite in an attempt to clean molds, until it generally no longer bleaches the mold stains out and/or the molds rapidly return, it is likely going to take you additional time & money or Corte-Clean® to initially clean  composites due to the need to “repeat” the application process, at “maximum strength” to “thoroughly dry” composites in “direct sunlight” between the temperatures of “65 to 85 F.” You may not have that instant “WOW” cleaning effect, almost all Corte-Clean® experience, especially if it is not used by following label directions. Your neglect to properly proactively routinely Corte-Clean® may have caused weathering issues, caused by stains or items blocking the sun from evenly bleaching/fading/weathering your decking, which only the sun can naturally weather out over time.


Once thoroughly Corte-Cleaned® it is best to initially routinely apply Corte-Clean® more often than Spring & Fall. We would recommend before composites receive moisture, or when stains are first noticed to ensure composites remain thoroughly clean. This will ensure stains do not deeply saturate while removing new spores, that have landed on the composites before they hatch & colonize. If you notice stains coming back, after composites receive moisture, you will know you didn’t thoroughly Corte-Clean® composites or proactively Corte-Clean® them often enough. Get ahead of the problem, if you wish for composites to generally ultimately stay clean for longer & longer for less & less!


The best time to Corte-Clean® mold stains or other fungus stains from porous composites, including this TimberTech® deck, is when they have been allowed to THOROUGHLY DRY, as stated on the Corte-Clean® label directions. If the molds look black & oily, the composite is not thoroughly dry. Do not use Corte-Clean® if composites are not thoroughly dry, as you will likely be wasting time & money!


Unfortunately, fairy dust won’t clean composites. We have designed Corte-Clean® to be as environmentally responsible as possible, however it is a proprietary blend of chemicals & it must get composites clean. To make it even more so, try to figure out how little Corte-Clean® you can use, once thoroughly Corte-Cleaned®. The less Corte-Clean® used, the more eco-responsible it becomes. The goal is to make sure you are ultimately spending less & less time & money keeping your composites clean for generally longer & longer periods of time, but if one cuts corners, this person is likely wasting time, labor & money resulting in the rapid return of stains. DO NOT SKIP THE FINAL CORTE-CLEAN® LABEL DIRECTION WHICH STATES “When Corte Clean no longer becomes dirty or discolored, it can be diluted & allowed to dry on weathered composite surfaces.

Diluted Corte-Clean®, at the “routine cleaning” strength, drying on weathered Trex®, before a rain storm to keep this composite deck clean, at the lowest possible cost, with the least amount of time, labor or effort, while being as eco-responsible as possible. Notice how the Trex® is no longer turning yellowish brown from tannin bleeding. If tannin bleeding is still occurring, or Corte-Clean® is still becoming dirty or discolored, one must repeat the Corte-Clean® application process, prior to allowing Corte-Clean® to dry on weathered composites. Always make sure any Corte-Clean® white residue is thoroughly rinsed prior to using composites.



Corte-Clean® is designed to continue to clean any time it receives moisture. A white residue may remain until thoroughly rinsed (use a brush if necessary). Thoroughly rinse prior to use.” The best way to thoroughly rinse is to proactively apply Corte-Clean®, at the “routine cleaning” Corte-Clean® strength, before composites receive natural moisture from rain or snow. This final step will ensure composites remain clean, while removing deeply rooted or saturated stubborn stains over time. Always make sure composites are thoroughly rinsed, prior to using. If you are not willing to recognize the severity of the problem & properly use Corte-Clean®, by following its label directions, you will likely be a dissatisfied customer.

PLEASE DO NOT PURCHASE & USE CORTE-CLEAN® if you are not willing to buy enough to thoroughly clean composites & keep composites clean, as you are likely wasting your time & money. Failure to review the Corte-Clean® websites, or at least watch the demo video & carefully read, comprehend & follow its label directions, will likely result in you being dissatisfied with our proven product, as unfortunately some customers experience. You have likely already tried using multiple other perceived inexpensive cleaning products, wasting much valuable time & money while making cleaning problems generally cost more time & money to thoroughly Corte-Clean®!  Do not cut corners or get cheap if you choose Corte-Clean®, as you have likely already been dealing with a rapidly returning serious problem, wasting much time & money, resulting in you finding Corte-Clean® & taking the time to read this to understand the problem & properly clean & routinely maintain an expensive composite deck, dock or fence!

NOTE: Corte-Clean® does have a “Best If Used By:” date on every 2000A bag, which is one (1) year from when it is manufactured. The fresher it is, the better & faster it generally works, especially when first used to clean neglected or improperly previously cleaned composites, so we recommend buying it directly from its website or a reputable retailer. Please DO NOT purchase more than you will be using in one (1) year from the Corte-Clean® website. It will very likely fail you. Corte LLC does NOT Guarantee or Warrant Corte-Clean® after the “Best If Used By:” date on every bag. Corte-Clean® IS a cleaning chemical specialty product, which has a Safety Data Sheet (SDS) & will be shipped with Precautionary & Hazard Statements. READ & FOLLOW THEM. Corte LLC does NOT accept returns of Corte-Clean®. Make sure you want it, before you buy it. You can always buy more, when you need it. If you have reviewed the Corte-Clean® websites & have any questions before one purchases/uses or after Corte-Cleaning®, especially if the desired results are not reached, before posting a negative review, please have the common decency to take two (2) digital pictures, one when the deck is dry, the other when wet, with water to magnify stains &  Contact US so we can help you!

Corte-Clean® cleaning Trex®





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