When I dripped more e-liquid into my prefilled cartos that I thought had been used up enough to accept more, I dripped it into the top (not attached to a battery) till I saw iiquid on the top of the filler stuff. When that looked juicy, I blew through the hole. I set it on a kleenex to absorb a little liquid that came out, then waited a while for more, cleaning off the ends with the kleenex, and then first used it on my manual battery, just to be sure. All seemed to be OK. Did I do it right? It seems I did. And when I use the condom method, can I just do the same to be sure of no leaking or overfilling?
I have only used the condom method when filling a new blank carto. Then top off with juice when needed, by dripping. Seems to me if you use the condom method on one that is already "wet" even just a little, will be to much and cause problems. I have never had one leak, but I did have one gurgle and spit into my mouth, but was easily fixed by spinning and blowing. I do not ever want it to spit into my mouth again. My tongue was numb for a couple hours where the juice hit. Not fun, not to mention it was nasty! lol