We have a large Trex composite deck and, over the years, tried pretty much every cleaning product out there, with less than satisfactory results. We tried Corte Clean this year and found it to be the only product which could "get the job done" with regard to removing both black and green mold and other stains. Our deck has gone from unsightly to looking "like new", simply by following the Corte Clean directions and applying the product at the recommended intervals. Corte Clean is a product which does exactly what the manufacturer states it will do. We'll never even consider using anything else.