I recently acquired a used Colt Sporter Match HBAR 20" AR15, A2 configuration rifle. The cop I got it from treated it more like a tool than a fine firearm. Cosmetically it is a tad rough, but functionally it rocks! The portion of the barrel that extends past the front sight post, the front sight post, and bolt all have spot rust on them. None of it appears to be deep, and after close inspection I have not noticed any pitting (thank the Lord). Other than a nylon brush and solvent, does anyone out there have any suggestions on how to eliminate all of the surface rust without marring-up the finish? As always, any useful information is appreciated. Thanks. Yall stay safe.