I have a Remington 11-87 that has a parkerized finish. This weekend, I did a little camping and trapshooting, and -no foolin'- we got FIVE INCHES of rain. Aside from a sleeping bag that weighs 400 pounds, the humidity got to my shot gun (which was in the truck). There is now a light coat of rust on the receiver (just the side that was up) and a little on the magazine cap. How the heck do I go about taking the rust off without shredding the finish? Any help would be greatly appreciated.