Whugett, this is strictly my take on the actual cleaning effect. Please dont take it as a slight.
Ok, here goes. There is no cleaning action by the wads. None. Any fouling from previous shots is in front of a press fit ball. The ball will push out any soft fouling, kinda like squeezing out the last little bit of toothpaste. As for fouling from the current shot, its behind the wad. High pressure gas is pushing the wad against the ball at 8000 to 10000psi, or more. The lube is squeezed out of the wad and vaporized by the pressure and possibly the heat. Its the same concept of how a diesel engine works. I believe the vapor coats the bore and possibly mixes with the fouling, carrying it out of the bore. The vapor has more weight and momentum than the ash from burning black powder, so pulls it along for the ride. That's the reason the bore is clean immediately after shooting.
And there you have my personal take on that. Everyone is free to disagree, no offense taken.