铜锈 meaning in English

patina

Method for scale adhesion test for oxygen - free copper
无氧铜锈垢粘着力试验方法
Restorers have so far removed more than two thirds of the dull patina which had been obscuring the statue
到目前为止，修复工作者们已经清除了超过三分之二的暗灰色铜锈，这些铜锈使雕像失去了光泽。
Instructions : the product can deoxidize the coppers . it contains certain friction producing substance and can remove the rust completely without damage the copper
产品说明：该产品能将铜的氧化物还原，并带有一定的摩擦剂可以彻底去除铜锈，并且不伤铜材本身。