Removing corrosion from wheels

[rocklyons]

I recently purchased 4 chrome wheels for my 95 Convertible. There is some white corrosion (a friend said it is caused by electrolisys) in the cut-outs. I realize that where it has eaten thru the chrome there isn't much that can be done but what is the best way to remove as much as I can? Also is there something I can use to prevent it spreading?

Rock