After finishing what looked like a clean bore using Shooter Choice, I decided to try some Kreen which is made by Kano Labs, makers of Kroil. Kreen is intended to remove sludge and carbon inside engines so I figured why not carbon in a rifle bore.. I soaked my bore brush and ran it thru 10 strokes and ran a patch thru. It came out black! I thought Shooters Choice had cleaned it after getting nearly clean patches out of the bore. I repeated this 5 times before the patches started to clear up. Once I finished with the Kreen, I rinsed the bore with brake clean, dried it and treated it with Militec 1. I was surprised how much carbon came out after the SC cleaning. I did another rifle with Kroil with similar results except that the Kroil was more oily than the Kreen. Thought I'd share the results.