I use four of them for when I'm out and about and haven't cleaned them. I know a couple have been refilled 4-5 times and they keep going. I did trash one with some 100% VG cappuccino that was too thick. I decided to toss it versus going through the hassle of trying to clean it. If they keep holding out like they have, I'll never try cleaning them.
I don't think I'll clean mine anymore, either. I cleaned 11 cartos the other day using water that I had brought to a boil, let them soak for 10 minutes in a container, and then pushed water through them using a 10mL syringe bought at Walmart. The next day, after I dried them overnight by a fan, two of them wouldn't vape. One seems to be completely dead and the other will vape just a little, but I know something is wrong with it.
I just cleaned them again, pushing hot tap water through each end using the rubber cone thing that comes with the Walmart 10mL syringe. After they dry, I'll see if they work, but I don't expect them to. I know they're not burnt inside, but something is messed up with the built-in atomizers, I'm sure.
I can't believe I spent the time to mess with them today, knowing they only cost $1.59 each and I've refilled them at least 8 to 10 times in the last two weeks.
This is still an obsession for me, I guess.