Used on fiberglass and painted aluminum. Do not dilute. Our amazing boat scum product will clean scum and grim from the bottom of boats, sides of campers, RVs, and siding safely and effectively. The formula is water-based, acid-free, environmentally-friendly and biodegradable. JJV's Best is a revolutionary product that is safe on fiberglass, painted aluminum, camper and RV exteriors, wood decking, docks, swim platforms, most sidings, cement sidewalks and more. Works without hazardous acids or scrubbing. Just spray it on let it dwell a few minutes and pressure wash off. For complete directions please visit our website. Note: Will not remove heavy lime deposits.