Removes stains from dirt, mildew, algae and fungus on a range of outdoor surfaces, including wood and composite decks, fences, concrete, masonry, brick, stucco, outdoor furniture, roofs, siding and some fabrics such as awnings and vinyl plastics. It is an effective, oxygen powered cleaner concentrate that is biodegradable and gentler than chlorine bleach-based formulas. Oxygenated Foaming Action. Removes Stains From Dirt, Mildew, Algae and Fungus. Non-Bleach, Chlorine-Free Concentrate. Gentler* Biodegradable Cleaner.