SW 503 H.D. is a Non-Etching Aluminum and Stainless Steel cleaner and polisher. A ready to use biodegradable liquid acid surfactant formulation designed to effectively remove dirt, oils, road film, soot, corrosion and oxide film from polished metal without etching or pitting. Apply with a plastic spray applicator. Avoid overspray and drying on surfaces. Contains Sulfuric and Phosphoric Acids. Buying more than two at one time will incur a hazmat fee.