How to clean a Trex composite deck. I used CorteClean deck wash to clean this deck. After you have built your deck , I recommend cleaning your deck at least twice per year to keep it looking good and to help prevent mould and mildew. Some decks should be cleaned more often depending on your environment. Always follow the directions on the Corte Clean package and the care and cleaning guidelines for the decking product you may have on your deck. Don't forget to wear safety glasses and protective gloves . To see more of our work visit us at www.yourdeck.ca