Safe Acid Plus is a multipurpose cleaner with a formula containing a special blend of surfactants, organic salts, and proprietary additives to create an acid replacement with a pH of 1- making it biodegradable and safer for the environment. Safe Acid Plus has the high cleaning power of acid, but is safe and gentle on the skin. Safe Acid Plus is highly effective against rust, calcium, scale and lime deposits, soap scum, stains and soils, hard water stains, beer stone/milk stone, scuff marks, and grease. The concentrated formula may be diluted with up to 25 parts of water, or used full strength. Always rinse with water.