CLR Pro CL-4Pro Calcium, Lime and Rust Remover, 1 Gallon Bottle Patented calcium, lime, and rust remover for cleaning multiple surfaces including stainless steel, glass, fiberglass, ceramic, porcelain, chrome, cement, stucco, brick and more Powerful non-toxic formulation effective on hardest of lime and calcium buildup Great for cleaning coffee pots, coffee makers, commercial washing machines, dishwashers, vinyl siding, sinks, toilets, humidifiers and filters, hard water stains; for use with pressure washers Safe for plumbing; safe for use on light-colored grout; septic safe; biodegradable; not harmful to nearby grass, shrubs, or vegetation EPA's DfE formula for safer chemistry; USDA Certified Biobased Product, 80 percent