Depends how rusty I refurbished one I was given by taking one of the brass .50 cal brushes and getting some OOO steel wool. wrapped the brass rod with steel wool saturated it with solvent and then threaded it onto the ram rod then chucked the ram rod in my drill and just ran it up and down the barrel for a while changing the steel wool as necessary. I'm sure I removed some of the threading and ruined some accuracy but it cleaned it up real nice. Some people might not agree, but it was the way I went about it.