Exterior Inc - The Gutter Zap Gutter Stain Remover is formulated to remove black streaks from gutters caused by the electrostatic bonding of tar and asphalt. Gutter Zap cleans black streaks off factory-painted metal and fiberglass such as gutters and RVs effectively eliminating grime. This eco-friendly 100% biodegradable concentrated formula not only removes heavy soil dirt and industrial stains especially those pesky tiger stripes on gutters but it is also designed to be non-toxic and safe for use around pets and children when used as directed. Gutter Zap is easy to apply; simply spray on and rinse off with garden hose pressure and it will not harm vegetation or painted surfaces when used according to directions. Featuring special sheeting agents for easier rinsing Gutter Zap now comes in a commercial concentrated formula for even more effective cleaning. Net Quantity: 32 fl oz (1 Quart).