Nauti Hull Clean is a phosphoric acid based product that is excellent at removing rust or red/orange based stains. This product can be used on almost any surface to remove rust stains, including yachts, boats, car exteriors, home exteriors, driveways and even bathroom tubs and tile. Nauti Hull Clean is excellent at removing oxidation as well. It is a forgiving acid and not harsh like some acids can be. Simply apply to the stained area and when the stain is gone, rinse off.