We have almost 500 ft. of decking.This year it looked horrible, black spots all over. I thought it was stains from my outdoor plants, but as I looked for ways to clean composite decking, I read the testimonials about Corte-Clean I realized it was mold spores on my deck. I went to Lowe’s & bought 2 packages that were soon to expire (didn’t think it would make any difference). Cleaned the deck twice at max. strength, it was clean but mold spores still remained. I talked to the manufacturer of Corte-Clean & he sent me 2 pkgs. of his product. Cleaned the deck again at max. strength, mold spores are gone!!!!!!The manufacturer couldn’t have been nicer. He returned my call promptly. I have called him at least 5 times & every time he answers all my questions, giving me advice, & says call me anytime you need to. I couldn’t be more pleased with this product. Will order more in the fall.