Ok this is probably a really stupid question but; the P pup on my memphis has a bit of surface rust on the round spots (which I used to know what they were and totally forgot (magnets or magnet surfaces??)...brain cramp so for sake of argument they are 'chrome round spots' ) on the face of the pup. Can I file/clean that off and not mess up the pickup? The thing sounds so sweet so its all working ok, just some age on the surface of the pickup that I don't want on there. Thanks for reading and once the laughter stops an answer would be nice. LOL!!!!