This is messed up, this is for my singers guitar that I am trying to help get clean.... He has a cat that pee'd in his case and naturally he sprayed some enzyme cleaner in it. Anyway, he put the guitar in the case and opened it a few days later at band practice..... The frets, the locking nut, the tuning pegs and keys, AND strings are all rusted or green. This isn't a little wipe off and go thing either...it's CAKED on there, the strings broke from the rust build up. Will brass cleaner or lime away type stuff clean it or is he screwed???