ATS cups are a machine finished wheel, and therefore be extremely difficult to duplicate the original finish, so probably your best bet would be to have them professionally refurbished, or possibly selling them, and putting the the money towards a new set, but that would of course have to be worked out with a price to refurbish, as to whether its worth it..
To do them yourself, you would need to paint stripper the entire wheel, sand, and rub out any corrosion, chips or damage with 120grit wet/dry, and working your way through 180, 320, 600, 800, 1200, 1500 wet/dry, and then finally polishing with a tube of "Autosol Shine" (
http://thepolishingshop.co.uk/acatalog/Metal_Polish.html ) and a lint free cotton cloth, with enough elbow grease, you should get a near mirror finish! painting should be done AFTER polishing, just mask out the area you dont want to paint, and carefully "Key" the bare alloy with 180 grit, but used "Dry" etch prime, prime, and paint, easy as that
AVOID re lacquering the bare alloy, as this is what buggers the wheel finish in the first place, just a quick rub once a month, with the polish, will keep them mint
A machine refurbish would cost something like £35-£60 +vat per wheel, so check out price of new wheels before committing!
Tom