锉刀用久了,往往在锉刀的齿缝里,嵌入各种金属粉末,如铁屑铜屑等,使锉刀弄得不好用了。现在告诉你一个刷新的方法:把锉刀浸入稀硝酸溶液中,稍等一下就取出用破布或旧棉花擦干表面,使硝酸溶液只留在齿缝里。等半小时后,再用清水把锉刀全部洗净。 File used for a long time, often in the filing of the file, embedded in a variety of metal powders, such as iron scrap copper, so that the file made bad use. Now tell you a refresh method: the file dipped in dilute nitric acid solution, wait a moment to remove the surface with a rag or old cotton dry, so that nitric acid solution only in the teeth. Wait half an hour later, then all the files clean with water.