I'm working on cleaning up a very pitted old sousaphone. On the bell, fingernail polish remover worked to take the lacquer off. On the body, it doesn't do as good a job. I'm going to try a metal stripper next.
Saxophones would be much more difficult because of all the keywork. If you don't take them off, you'll be sorry. If you do, getting them all back on right, without stripping any screws, etc., might be quite difficult.
I'll let you know how the stripper works.