Bought my first "new" rifle, a NIB CVA Hunter Hawkin. I know, nothing fancy, but I've had great luck with the used cva's I've bought. Anyway, bore is black, not powder residue or anything, more like preservative, I'm assuming cosmoline or some such thing. What's the best way to clean the bore of this. I can't use anything that will ruin or discolor fiberglass. Thanks for any assistance.