Sorry, but I don't know much about locksmithing or what terms to use. My brother has an ancient key which he hardly ever uses, but it has worked for many years. Unfortunately his kid has been using it as a scraping tool, and now the high point near the tip has worn down to the point where the key is unusable. He says a locksmith hasn't been of any help, because it's so old (for all I know, it just might be about my brother being stubborn about doing things himself, though). I was thinking that if we could find some kind of "liquid metal" that would adhere well to brass, he could add some of that to the tip and then file down any excess. And then get a copy made, of course. Does this idea sound like it could work? (If the material just breaks off in the lock it'll only make the problem worse.) Any suggestions on what material to use?