Yeah well that is and always has been a problem for mine. Whenever I unscrew it the chamber cap comes off in the tank taking the two mesh wicks with it. I have to use a tiny pair of needle nose pliers to get it out and re assemble. I thought perhaps the oring on the chimney was too thick to not allow it to come out and I have been hoping each time that would not happen but it does
I roll them on a sewing nettle, kind of a regular sized one and after pulling it out continue rolling in my fingers till it slide nicely into the hole. You don't want them too tight though.
Be careful when unscrewing the tank that you don't start unscrewing the part that the tank screws onto from the base/body, hold it by the knurling closest to the tank and by the tank.