Krud Kutter House Wash gallon. This major breakthrough in house wash technology, the proprietary formulation of Krud Kutter House Wash contains Sporex, a unique additive which removes tough stains from mildew, mold, algae, fungus and moss, and leaves the surface completely clean. In addition, special surfactants penetrate the surface to safely and easily dissolve the toughest stains from dirt, oil, grease, bird droppings, tree sap, and acid rain. It even removes gray weathering on wood, chalking, and oxidation. This product is safe, fast, effective and is recommended for exterior siding (wood, vinyl, aluminum), roofing, gutters, wood fences and decks, stucco, brick and cement block, masonry, concrete driveways, walkways and walls, even patio furniture, and boats. It contains a proprietary blend of biodegradable surfactants, detergents, and emulsifiers, in a water-based solution and has no petroleum solvents, bleach or ammonia. One gallon washes 4,000 sq.ft.