While troubleshooting the annoying hum my P-Bass Lyte has developed I discovered nickels...actual US nickels... underneath all of my pickups. I bought the thing new in '89 and I was wondering if it was a common practice for Fender to tweak the machine in this way. Oh, and I'd also like advice on how to fix the hum. It sounds like crappy grounding, but the electronics guys can't find any problem with it. Could it be a shielding issue?