I've been using Break-Free's new Bore Cleaning Foam for the past few months now with good success(judging by the blue-stained patches that come out of my barrels). It's convenient to use(squirt the foam into the chamber until you see it come out of the muzzle, wait 15 minutes, patch out), doesn't stink like ammoniated copper solvents, and supposedly won't harm your bore if you neglect to wipe it out quickly enough. It's a little pricey(around $10-12 a can), but it seems to go a long way. Like any other copper solvent, though, you should use a regular bore cleaner to remove the carbon fouling first.