BioGuard Off The Wall removes most stubborn scale, metal stains, grease and common dirt. It clings to vertical surfaces for easy cleaning. May be used on plastic, vinyl, fiberglass, ceramic, stainless steel, aluminum, and painted surfaces. Unlike many household cleaners, this product surface cleaner is compatible with swimming pool or spa water. Do not use on copper, brass, marble or galvanized surfaces. Do not allow undiluted material to remain on porous surfaces such as masonary bricks for extended periods of time (30-60 minutes).