SIMPLE GREEN Oxy Solve Concrete and Driveway Pressure Washer Concentrate 1 Gal. Meets the rigorous criteria of the U.S. EPA’s Safer Choice Program. Safer, non-toxic and biodegradable formula. Uses the natural power of peroxide for high-performance cleaning and stain removal. Lifts off tough tree sap, grease and oils from driveways and walkways. Eliminates discoloring from algae, moss, mold and mildew on brick and stone.