Spray & Forget - Roof Cleaner - House & Deck Outdoor Cleaner, Spray & Forget, is a revolutionary cleaner that removes and prevents unsightly and damaging green and black algae, mildew, fungus, and lichen stains from roofs, siding, decks, brick, stucco, outdoor furnitures and other exterior surfaces. Spray & Forget is available online and through select hardware retailers.