If you mean the new enclosed dual
coils they can be re-built but a bit of a pain in the a*se to do. I re-build them to a vertical coil and the vape is amazing.
The first time you do it the easiest way to get the chimney off is take out the bottom pin and gromet and pull the old
coils out from the bottom. Then use something like a 3mm drill bit with the flat side in from the bottom and give it a wack with a hammer. Assuming they are genuine
coils they can take quite a lot of punishment and you should find the chimney will "ping" off. Once it is off getting it off a second time is easier and you can use pliers and pull it off.
http://www.e-cigarette-forum.com/fo...ed-kanger-dual-coil-single-vertical-coil.html
One one of the pages on my post about rebuilding them vertical someone else has posted how they use them as a standard horizontal coil as well.
Hope it helps.