염산
Notable descaling agents include acetic acid, citric acid, glycolic acid, formic acid, lactic acid, phosphoric acid, sulfamic acid and hydrochloric acid. The calcium salts are soluble and thus washed away during dissolution or Solvation. The speed of the descaling action depends on the concentration and acidity or pH of the solution provided. Hydrochloric acid is much stronger than acetic acid for example, so tends to remove scale faster. Weak acids such as acetic or citric acids may be preferred however, where damage to the substrate is to be minimised.