Six or seven years ago, my husband and I decided to install a composite deck because we were tired of refinishing our cedar deck every year to keep it looking nice. Unfortunately, nothing is 100% maintenance free and our deck started getting spots everywhere and started turning green and black in sections where there is a lot of shade. We tried regular soap and water at first, then tried some other products from local stores. Nothing was removing the spots or all of the dirt. I did a little research online, came across this product, and decided to give it a try. Last weekend, my husband and I used the Corte Clean product for the first time. What a difference! Our deck almost looks new again and all of the spots and dirt have virtually disappeared. I am someone who has very high expectations and this product actually left me pleasantly surprised. Definitely worth the money and a few hours of your afternoon.