I have only used the Joye cartomizers, and I've used a ton of them. I just ordered 20 more to replace the ones I bought two months ago that are now dying. I have a bowlful of them I keep refilling. Some last a long time and work great. A few died after only a single refill or so. Keep in mind that the filament of the atomizer inside is similar to a light bulb, but less dependable. Lightbulbs don't get a variety of different chemicals run through them, and they operate in a vacuum.
I used to wash my cartomizers, and I know a good routine for doing it, but it's a major pain and I don't think it's worth the effort unless you have a bad tasting juice you want to flush out. If that's the case, you can remove the mouthpiece and the plastic barrier below it, exposing the fill port. If you have filled the carto with a syringe, or have already pierced that fill port for any reason, that gives you access to air and water flow through the filler. If you don't open that port, you can still pass air and water through the carto, but it's only going through the air shaft down the side, not directly through the filler. This may flush the atomizer, but not the filler, so the juice remains inside.
Once you have that pierced fill port exposed, you can use any method that forces air or liquid through the carto to blow out or flush out any juice inside. If you are looking to clean everything inside, I'd recommend Everclear or grain alcohol, high proof vodka, or something high in alcohol purity. You can just inject it like you are filling the carto with a syringe, then blow it out forcefully with your mouth or an air pump. The alcohol will dissolve any crud and it dries very fast, especially with air flowing through it. I've even used canned air, but the kind of needle you insert into a basketball to inflate it will fit into that fill port with a little coaxing, and you can then use compressed air or a bicycle pump to force air in to dry out the alcohol inside. Careful not to use a high PSI air source or you'll blow the carto apart or send it through your neighbor's window!
Like I said, I rarely clean them anymore. Too much hassle for something that costs less than a fourth of the price of a pack of smokes.
Also, I've noticed that some e-liquids seem to kill cartomizers faster than others. There is no guide for that. Hit and miss, live and learn.
One last note... I don't know why, but it seems the ones I've bought most recently are dying faster than the ones I bought two months ago. And they are very slightly different in the size of the mouthpiece and the tightness of the battery threads, so something changed, but the vendor is not aware of any change. She said I'm the only one to report problems with the newer ones, so far.
