I own a coffee maker similar to the one in pic related. It's made of aluminum. My flatmate who compulsively puts things in the dishwasher has put it in the dishwasher, and now the aluminum is completely oxidized. Are there any household products that you know of that can clean off the aluminum oxide, and possibly stop it from oxidizing further?

I know a small dose of lead rapidly delivered to my flatmate's head might take care of the latter, but ideally I'd end up with a good as new coffee maker as well.