Goof Off 1 Gallon Rust Stain Remover is a fast-acting solution that tackles rust stains on various surfaces, including metal, paint, concrete, stucco, asphalt, enamel, tile, and more. It effectively reacts with the iron in rust stains, neutralizing and removing them from almost any surface, whether painted or base, indoors or outdoors. Use it to eliminate rust stains from grout, sinks, tubs, toilets, dishwashers, counters, and outdoor problem areas. It even works on tools. It's a convenient choice that saves time and money.