I finally started using this on my guns about 6 mos ago after reading about it here. Most of my guns have been fairly well cared for in the cleaning department so it always seemed to work well but it never had a "real" challenge.....Til today. My dad is retiring and building a place in the country , so he decided he needed to sight in his 22lr for pest control. Now I haven't seen this rifle since I was 12 (30 yrs ago) and I don,t think the action had been cleaned in 30 yrs prior to that. It would only fire 3 out of every 5 becuse of weak firing pin strikes and would only eject every other empty. Man that was the dirtiest rifle I've ever seen, the carbon build up was so old and thick it would have been a diamond in another month or so. Well anyway I took every pin, part, spring, and screw apart and sprayed them down with the GM cleaner, let them soak about 15 mins, then took a tooth brush to them. The results were amazing, the dissolved black carbon just melted off the parts, only one part needed a second application and it required no soaking time before brushing. I knew this stuff woked from prior use but I had no idea it was that amazing. I would highly recommend trying this if you haven't yet. Truly outstanding stuff.