The only destructive type of corrosion occurs when chlorides react with the metal to form cuprous chloride. Yang stresses: "Cuprous chloride absorbs oxygen and moisture from the air and produces cupric chloride, a powdery substance that will just keep on eating away at the bronze unless you put a stop to it.
楊源泉強調，氯化亞銅在大氣中吸收氧氣和水分後，會生成鬆軟的粉末狀鹽基式氯化銅，如不加以遏止，就會不斷腐蝕銅質內部，「這就是『銅器病』。」