Shooting technical advice

MIKE GEORGE

All really effective polishes are likely to remove metal to some degree, as they consist of tiny abrasive particles in either liquid or wax.

You use a very slightly abrasive polish every day when you clean your teeth, but the abrasive element in toothpaste is usually nothing more than relatively soft chalk I would be tempted to try with Brasso or some similar metal polish, and if this doesn’t work then get the gun professionally cleaned by a gunsmith.