I get a small bowl, put the cartos in, cover them with denatured alcohol, and let them set overnight. Sometime the next day, as was posted above, I turn the hot water on, hold a carto with pliers, and give it a hot water shower to get the alky and whatever is left out. I then blow the water out and let them set for a couple of days to air dry. Hardware store will have the denatured alcohol. It's usually around the paint. Walmart also has it in their paint section.