Polishing alloy levers?

I've got some old record ergos (9 speed) that I've had fixed up internally but they're in a pretty sorry state externally. They've been used so much the bit where I usually have a finger or two across them have dulled to the extent they are almost brown. How would I go about polishing these up? Is there a particular implement I should use? How much work would it take to get it into a nice condition/like a mirror?! I'll have some time on my hands at some point soon so this could be a mindless but hopefully satisfying way of filling it.