Is there some way to repair/ stop corosion where the gold color has been scratched off? Appearance is not as important as stopping the corosion.
Repair is difficult, but stopping the corosion is relativly easy. Wire brush all the corrosion away and then coat lightly with oil. Clear nail polish also works but I've found you have to keep after it just as much as the oil.
Ron
gotta' disagree w/ Ron, a bit (all ye metallurgy experts, please jump in to correct me/us):
clean, sand, polish, remove any polishing agent & DO NOT COAT w/ ANYTHING -- LET IT SIT & OXIDIZE in a salt-free environment (not sure how long, so give it a while 'til you get a dull grey color w/ no shine)... Aluminum Oxide forms naturally; unlike FeO2 (rust), AlO2 is harder, smoother, more corrosion-resistant than the elemental metal & it's non-porous, so oxidation stops once the AlO2 layer is a couple molecules thick. Anodizing is just a chemical/electrical process for making that AlO2 layer much thicker, more scratch-proof & longer-lasting.
AFTER you do your homemade pseudo-anodizing, THEN coat for added longevity with something that is NOT CLEAR, so you can easily tell whether the coating is still there