Yes! Then use a wire brush like caution mentioned! I used the rotary tool brass wire brush on the contacts. Springs are a little bit of struggle with hands.Funkateer38 said:50% sodium bicarbonat + 50% Vinegar in a cup works fine
or with a brass brush
yes...I've used apple cider vinegar and it worked great.caution said:I soak them in apple cider vinegar for a day or so, then use a wire brush to knock off any remaining chunks.