Some guys plug the barrel. I've done that in the past but have gone to coating the bore with varnish or clear laquer. Remove it with acetone after the final boil. For carding I use a carding wheel in a drill press @ 600rpm. You can also use degreased 0000 steel wool. For the hard to get places you just have to be creative, a hemostat and small wads/pieces of the degreased wool is the way I do it.
