Originally Posted by
wroomwroomoops
For further reading/thinking: most any acid will remove rust - because rust is (mostly) ferric oxide, Fe2O3, and reacts with (and is dissolved by) even such weak acids such as carbonic acid - present in sodas and Coke and such.
The most common acid used for rust removal is phosphoric acid.
Just be careful, though! Given time, any acid will react with steel, and will react even more quickly with aluminum. I'm not saying it won't work fine, but don't leave the parts laying in acid for too long.
Oh, and citric acid is better than phosphoric acid because it chelates metal ions. EDTA, (not disodium or tetrasodium EDTA,) would be better, but it's rather expensive and much more difficult to find.