I think using the Flitz metal polisher would be the best choice. I havent used it, but from what I heard it is excellent stuff.
I actually have a tube I'm about to use on beloved Cold Steel kukri cause I negelcted and it has alot of hardend dirt and rust on it.
I asked my question in Shop Talk and everybody screamed "USE FLITZ! IT'S KICK ASS S*** FOR EVERYTHING!"
So I'm going to try it this weekend, I'll let you know how it works.