Guys, I usually clean my own guns and never see this afterwards. I dropped it off to have it cleaned before turkey season so that it could be completely broken down, cleaned, and reassembled before turkey season. The barrel looked clean to sight and there was lube in the receiver. However, when putting the rag inside the receiver, chamber, and the exterior of the mag tube and pistons underneath the foregrip, this is what I got. I didn't get anything off the bore snake when running it through twice so the barrel was cleaned. Also, I spoke with a friend who is a much bigger gun nut than I and he said it could be Kroil, which I've never used. I've never had problems with this gunsmith but I wanted to get more advice before I accuse them of not properly cleaning the gun as paid for. Thoughts?