... deep removing rust and stubborn stain.2)No damage to surface gloss,deep clean,externinate recurrence of rust and yellow ... It applies to rust and stain on any polished-surface and matte-surface granite,marble,tile,polished tile,cement floor,wooden floor ... sand paper and in motorcar chassis before rust prevention,without any effect on rubber hose,sealed edge,electrical wire,etc. FAST & HIGH EFFICIENT ...