wd40 and lots of elbow grease?
i recently aquired an old set of arbiter flats, and it ws terribly rusted as well.
then i just polished it. took up quite a bit of time, which maybe difficult for you now cause army is shit, but it'll be rewarding i guess.
just my personal view, i'll be the 1st to admit i'm no expert, but hope this helps!
cheers,
joash