[Drbrown]

For the gauge faces, I recommend distilled water (available at most local grocery stores) with minimal amount of mild unscented liquid hand soap. Apply gently with a plain cotton cloth, pad or q-tip; avoid rubbing if possible. Do not use solvent based products (oil, alcohol, lacquer, acetone etc) or products containing abrasives. Rinse by dabbing with clean damp cotton cloth. Air dry without heat.

General: I sometimes talk to people at my local historical society or museum about cleaning and preservation methods.