Cleans Brightens Decks Fences and makes your weathered old deck or fence look like new. Moldex Instant Deck Wash removes tough stains from: mildew, mold, algae, fungus and moss. Formulated with Advanced Bleach Gel for removing deep mold, mildew, moss and algae stains. Ammonia-Free detergents for dirt, grime, food, and other organic stains. This product is the ultimate outdoor cleaner for all wood, or composite surfaces outside the house. Contains Active Cling Technology.