There's a thread going on right now over at Festy.com where a guy's describing how bad his piston rings where stuck. I mean he's got the block torn down and the pistons out of the car and the rings were a real bugger to get loose from those pistons!
I've turned him on to "Dawn Power Dissolver" which he's been using on all of the cleanup process to dissolve a lot of the baked on carbon buildup.
To bad he wasn't doing these piston soaks all along, a lot of what he's experiencing right now could have been avoided.
I don't have any dirty pistons to show you guys right now, but I can tell you they sure work a lot better when the rings are able to float in the lands like they were designed to do. The piston soak will help dissolve that inevitable carbon buildup short of tearing the engine down.