I clean all of my pots, pans and stoneware w/vinegar or even a wine that has went bad. It's like deglazing a pan to get the good juices up. You can heat it up and the put the vinegar in it to soak. I would recommend amonia; I take my barbque grill and oven racks; put in a large trash bag and put amonia in it; close if and let it set out in the sun; cleans it all up. I'm not sure if your crockpot would absorb the odor from it though; but if all else fails.