info on cleaning corroded bulb sockets, please!

On another thread it was recommended not to "sand" (and this was AFTER I had already sanded away a lot using the wife's emory boards) because it removes the top layer that is applied to new brass and/or copper as a protective finish. This is just what I read, so I don't know if that is truly an accurate statement or sound advice. I haven't found Deoxit in any stores around here yet and don't believe it's a new product either.