The WD-40® Multi-Use Product formula is ok to be used on plastic, rubber, and hard metal surfaces. This includes Acetal, neoprene/hard rubber, HDPE, PPS Copolymer Polysulfone, Teflon, Viton, steel, galvanized steel hot dip, electroplated, copper, brass, magnesium, nickel, tin plate, titanium, and zinc. Certain types of rubber will swell upon prolonged immersion. Wax polishes and certain wax coatings may be softened by WD-40. Clear polycarbonate and polystyrene may stress craze or crack. Always test surfaces first