I noticed a few blotchy looking areas on the side of the nickel finished receiver........, I tried removing 'em first with a little gun oil on a cloth, that didn't work. Then I tried a little solvent (Hoppes #9) on a cloth, that didn't work. Anyone got any ideas on what I can try that won't harm the finish? It's no big deal - I'm probably just being nitpicky I guess. Thanks in advance.