I would caution against using a wire brush. This will leave all kinds of micro-abrasions that will permanently damage the surface. I agree with your concern that some products may do more harm than good. Hard to go wrong with a foam or cotton swab and pure isopropyl alcohol.
Cleaning tube pins
Anyone have any suggestions for cleaning gold plated tube pins on NOS tubes. I have heard that Caig's is not the answer. Plus, I do not want to take the chance of removing the gold plating.