A metal polish that is safe and effective. We use P21S Finish Restorer on many exhaust tips. Over time, the road grime adheres to the surface of the tips and the carbon deposits create a black soot inside the tail pipes. Once the inside and outside of the exhaust tips are cleaned with P21S Total Auto Wash, we then use P21S Polishing Soap to clean the exterior and interior of the tips. This deep cleaning will remove almost all the imperfection and contamination on the metal surface. You can actually hear and feel the surface getting smooth. When the desired cleaning effect is achieved, you can then further polish and protect the metal surface with P21S Finish Restorer. This product is very effective, has no ammonia smell, and is safe for most metals. Simply dab a little of the past on a clean microfiber towel, and rub the surface until the true shine and depth in the metal is revealed.