Received a SAC gun yesterday in A-1 Special Trap Grade; the only affordable SAC gun in this grade I've seen for sale in 30 plus years. It's certainly far from new but is complete, has never been altered or monkeyed with, and has the optional Krupp barrels. The receiver is not pitted or rusty, but metal surfaces have turned a dark brown/grey; so my question to the experts here is how can I remove this dark "patina" from metal surfaces and improve the looks of this gun? Thanks in advance for your time. Tom
