I got in a nice marble Frenchie that had been in a fire. Looks like everything is gonna clean up fine. The only thing that is a question for me is this dial. It appears to be solid brass with smoke/ash/whatever coated on it. I don’t know what to use to remove the gunk without removing the painted numbers. Naphtha got it off the porcelain center section of the dial, but I’m afraid it would resolve the paint. Help?