Heat. Heat, heat, and more heat. I've lost count of how many frozen engines I've broken loose with the monokote heat gun. We've also got a heavy duty heat gun for stripping paint that I use to change bearings, etc. It's a bit overkill for the usual castor stuck wrist pin. I may use a little carb cleaner, PB blaster, and air tool oil, but far and away the solution for stuck parts is to grab a heavy leather glove and heat the stuck parts until the glove starts to smoke, then they come right apart.
The crockpot is only for removing baked on castor and crud, and only on certain engines. It'll turn a Super Tigre or OS the ugliest shade of murky gray, but works OK for Foxes. Anything decent, of any value, anodized, painted, or plastic doesn't go anywhere near the crockpot, and the crockpot will never put the heat into parts like a heat gun. The heat gun also does the job in seconds vs hours.