The longer you leave it on, the harder P21s Wheel Cleaner works!

Perfectly safe for all types of wheels when not used in direct sun or on a hot wheel. Spray on a cool, dry wheel, sponge evenly over the entire wheel surface to remove any drips or runs, allow to work for a few minutes and then rinse off all traces with water. Heavy accumulations of brake dust residue may require gentle brushing with a soft brush before rinsing and/or multiple cleanings. Our favorite wheel cleaner for heavy accumulations of brake dust.