CLR Calcium, Lime and Rust Remover is a powerful formula that quickly and easily dissolves and removes tough calcium and lime deposits as well as surface rust and hard water stains from bathtubs, toilet bowls, sinks, glass, chrome, fiberglass, stainless steel, most coffee makers, humidifiers, dishwashers, washing machines and shower heads. The formula also is perfect for use on RVs and boats. CLR Calcium, Lime and Rust Remover is part of the EPA's Safer Choice Program, recognizing the product as a safer alternative to chemicals. The fast-acting, powerful CLR formula is septic-safe and contains no phosphates. Always spot test in an inconspicuous area before beginning to clean.