I highly recommend blue magic. It works on all metals and even plastic and corian. I got mine at Walmart, but they have a website with a locator.
http://people.consolidated.net/cargoche ... olish.html
This stuff cleans and polishes. You put it on and it turns black with all the crud and then you polish off the black just as you would your car when the wax gets dry. A dremel is too fast and can burn the polish into the metal, but can be used if you careful. My drill worked better but takes forever. I must have 20 hours just in polishing now.
I decided that I am going to take it farther, by sanding out some of the casting marks left by the mold. There are some sharp edges that I can clean up too. Those mold marks are preventing areas of the key from shining as well as they could. I'm still undecided on what to do about the black plastic cap for the binding posts. I think it might look better without it. I wish I had a clear one instead of the black. Wonder if I can cast my own out of resin?