Birchwood Casey Bore Scrubber will remove plastic, lead, & copper fowling. If the build up is severe, you might need a brass bore brush. Dip the brush in the solvent and then scrub the barrel in nice long strokes. After that some solvent patches and your barrel will shine like new.

After you have the bore nice and clean then I like to use Birchwood Casey #77 cleaner. It has a foaming action to get into all the pores and what not to remove stubborn fowling and make the barrel shine. It will also remove most of the anti seize greases as well.

After a couple dry patches then protect the bore with Birchwood Casey Sheath also know and Barricade. While I am not a compensated Birchwood Casey spokes person, I have found something that really works for me and I stick with it.... Wish I was a spokes person, maybe they would cut me a deal on the stuff..