Another vote for the purge / compressed air maintenance.
I purge my lighters every time I fill them; only takes a couple seconds. They visit the air compressor in the garage every couple of months or so for a blow out with air. Many lighters use little pressed on plastic tubing inside them, so don't get too close to them with 100 psi....
Just enough to blow the ash and crap out of the jets....though, with good fuel, there isn't much if any.
I've been using King Butane (Googles right up) for some time and am completely happy with it. Very reasonably priced, and very, very clean. Stick with good fuel and purge before filling. Most problems are solved by this simple procedure.