I have used Corte Clean for close to 10 years.It works and works better than the liquid products. I have found that washing the deck prior to using Corte Clean with a detergent cleans the deck of superficial dirt. The product is able to more easily penetrate the fibers of the composite as I brush it in. It’s not necessary to brush it in but I think this allows a better job. No differently than painting with a brush as opposed to a roller. If the water does not appear dirty I do not wash the product off. A white residue remains. This washes off when it rains and allows the product to attack the mold again. I have found that using Corte Clean over the years has made the job easier and easier. Lee