I run a wet patch of Barnes CR-10 through the bore & let it soak about 5 min. then use a brush with CR-10. Run dry patches through the bore & you'll see all the blue crap come out on the patches. If it really bad, repeat the process until it's clean. If you use a bronze brush, rinse it out good, the CR-10 will eat it because there is copper in it. I give it a coat of oil & then use a mop to get the excess out. You wouldn't run an engine without oil, same goes for a barrel. Everyone seems to have different opinions on this matter. Who's right & who's wrong? This is what I do. I refuse to store a dirty gun.