I don't get these comments about the condom method being messy. I've been doing it this way for all my cartos without any mess. Anyway you fill you are still going to have to clean the treads with a paper towel so as not to get juice in the battery connection. If I have any juice remaining in the condom when carto is full then I just pour it back into the juice bottle. No mess and not fuss. It's simple and you can be sure that the bottom of the carto is saturated. Using a syringe is a pain and usually leaks juice out the bottom before the carto is full. So what's the problem?
We're talking about the juice on the outside of the cartomizer, not around the battery connection. It's not a problem, just personal preference I guess. As long as you get it in there and can vape, it's all good.
