Lemon Zap cleans black streaks off factory-painted metal and fiberglass like gutters, RVs, etc. caused by electrostatic bonding. Lemon Zap is easy to apply. Spray on and rinse off with garden hose pressure. This product will not harm vegetation or painted surfaces when used according to directions. Lemon Zap for Commercial -Use is a 100% biodegradable concentrated formula that removes heavy soils, dirt, and industrial stains, especially those pesky tiger stripes on gutters. It contains special sheeting agents for easier rinsing. 32 fl oz. (1 Quart)