Hiya BuckThunderThrust, I haven't had a K3, but I have a feeling they may work on the same
basis as the V3's.
Could you try unscrewing the tank at the bottom, where it connects with the battery base? Try gently
unscrewing the tank from the base. Of course you will need to empty the liquid out first.
Then that should leave the coil exposed and ready to unscrew.
As I said I haven't had one of these, so check to see if there are threads at the bottom of the
plastic tank first. If there are, then this would be the way to go.
Hope this helps.
Just edited to add: I'm looking at the pic on the site, and really can't tell if the bottom part of
the tank is threaded or not, so if it won;t unscrew then don't force it. If it had to be done via the
top of the tank, is there any way you could get some tweezers in to help?