That’s badass. I know they say not to clean, but in this case I’d be real tempted to. Not like you intend to sell it. Kinda like an old collectable firearm, you wouldn’t allow it to just keep deteriorating because it’s old and collectable. You’d bring it back as safely as possible to its former glory depending on stage of deterioration. A tough call with both guns and coins. Years ago I had a ‘83 Winchester in 45-70 that I had fully restored from a poor condition though the bore was perfect. It was a tack driver at a hundred yards and looked like it was just made yesterday when done. Didn’t lose a dime on it when I sold it, in fact it sold better than one with above average condition. Just barely below one rated mint. Wish I still had it! Lots of vids on jewtube on how to safely clean a coin. Would make a killer necklace cleaned up! I don’t know man, tough call!