There are a few videos on Youtube that explain different ways to clean out a cartomizer. PBusardo is one user to look up, for he has very good videos for reviews and tutorials regarding vaping that are both entertaining and informative. His method for cleaning is boiling the cartos in water till the juice is cleaned out. There are other videos that use an oral syringe to basically squirt water thru the carto till it is clean. Vaporyankee is one to look up on youtube, he uses the syringe/turkey baster method, and is quite funny to watch, but very effective as well.