Black Swan’s MURIATIC ACID is 28% hydrochloric acid, 18° Baume. It can be used to etch concrete floors and walls prior to painting, cleaning brick and cement, removing rust stains from toilet fixtures, removing rust from metal, and adjusting the pH of swimming pools. This product contains no inhibitors and will attack metal after rust is removed. To neutralize this acid action on the metal, make a solution of water and heavy duty detergent and rinse thoroughly. Then follow with plenty of water.