Corte-Clean® was designed to be used from the time composites are new “at least twice yearly, spring and fall, or when stains appear”; or a bare minimum of semi-annually as recommended by most composite manufacturers. Failure to properly thoroughly clean new composites made from exposed wood fibers of what is known as “tannin bleeding”, & especially those additionally made from exposed dirty recycled plastic (milk jugs, shrink wrap, cheese wrappers, etc.), of this & other dead organic dirty matter that lands on composites, especially before they receive moisture can result in stains from molds, mildews, lichens, mosses & algae & rapidly re-occurring stains, if not thoroughly properly initially & proactively routinely Corte-Cleaned®; especially if previously neglected, or scientifically unproven sodium hypochlorite based cleaners have been previously used. Once composites are thoroughly Corte-Cleaned® of their inherent flaw(s) and/or the numerous problems caused by neglect or the previous use of other cleaners, proactively routinely using Corte-Clean®, at the reduced “routine cleaning” strength, to remove new stains & stain causing derbies before they become deeply embedded is HIGHLY RECOMMENDED! Generally, the more routinely Corte-Clean® is initially applied, by following its label directions, less & less Corte-Clean®is mixed with water & applied at a lower strength, the more time, labor & money is generally ultimately saved. Many customers that properly use Corte-Clean® end up purchasing 1/2 or less to keep composites clean (example: if it takes two bags of Corte-Clean® to initially clean a nasty neglected or previously chlorine bleached deck, it generally only requires one bag to maintain it on a twice yearly, Spring & Fall, basis.) When properly initially done, composites are known to stay clean for longer periods of time; sometimes years.