Instant Hull Cleaner is formulated to begin working on contact to remove unsightly waterline stains. Very effective at removing rust or leaf stains from fiberglass or painted surfaces, the formula also instantly removes stains from grassy marine growth, rust, scum, and fish blood with no rubbing or scrubbing required. It will not harm the surface being cleaned and is an ideal preparation for polishing the hull. No rubbing or scrubbing required Will not harm surface being cleaned | Instant Hull Cleaner, Gallon