I found a rifle in the hills a couple year's ago. The stock and leather were toast and it obviously had been there for a while. The barrel and the action had a bunch of surface rust. I figured, I had nothing to lose so I disassembled, soaked the barrel and the action in Krud Kutter in a PVC tube with one regular cap and one screw in cap. After a couple of soakings, I scotch brited and steel wooled any place that had pitting left. I sent it to my gunsmith in Maryland where he measured everything and made sure the bore and the chamber were in good shape. After that he used a polishing wheel on the entire thing and it looks like it's new. At least for the chemical I was using, the PVC worked great. Good luck!
