To flush them, pull hot water into the syringe with the blunt needle attached. Fill the CE3 with water, or fill it as much as possible, then turn it rightside up and push the water through. It will squirt out the battery end and the air tube end. Pull the plunger back and suck waht water remains back into the CE3, then push down again. Do this several times, like three or four, and, of course, do it over a sink using the hotest water you can stand. Each CE3 is a little different when it comes to filling them with water. Since water is a much lower viscosity than liquids for vaping, it does "leak" out through the wicks into the air ways quite easily. It is not all that important to get it full of water, just get some into it. I use a 10ml syringe to flush them with and to fill them, saves a lot of time. If you're a Youtube accecanado there are some visoes from MrOutlaw that demonstrate how to flush them. It isn't hard to do, but can get a little messy when the water squirts out and you're not expecting it. A trick I use when I'm done is to shake them like a fever thermometer, mouthpiece end down, to make any remaining water move to the silicon seal. Then I use the syringe to vacuum that water out. With the wick wet with water it may take a few drags to get vapor production back, but it will come back to normal.
I am not sure on all the details as soon as I know for sure I will update
