it depends on the carto the first pos
ecig i got the cartos had a coil
through the middle but the newer lr cartos it doesn't obstruct the airflow by being in the middle so the old ones i pulled stiffing or and dripped onto the coil it was great for a while also could boil clean and heat dry by putting in front vent of a space heater on low within an hour the new lr cartos i got i pulled the stuffing out and tried the same thing leavinf only a small tightly wrapped peice of stuffing aroung the center of the coil and it dodn't vap right or taste right may be giving up on it you asked i mentioned what i tried
i'm sure you know the whole endcap filling thing if not just ask