Ok, so with the cartomizers how often do you clean them? I was watching a vid that says to boil them for 5 min. The sign your cartomizer is running on low on juice is when you get that burning smell or taste, correct? Can you put a different juice in when the other juice runs out, or should you clean them first before trying a new juice. Also I was idiot and put on a cartomizer without juice and tried smoking it lol and now its burnt, is it trash now? thanks