Hi there. It is in my experience best to leave the "dry burning" to ss mesh. Cotton, silica and other fibrous materials don't dry burn well, otherwise u do exactly that--burn them.
Silica wicks should be heat-resistant up to several hundred degrees F--high-tech synthetics or ceramics like Nextel even higher. If you are destroying silica wicks when you dry burn, you are doing two things wrong:
1) you are dry-burning them for too long. You want to hold the button on your PV JUST long enough to get the coil to glow. AS SOON as it starts to glow completely, let go of the button. If the coil is still gunky-looking when it stops glowing, then hit it again--ONLY until it glows, and then stop. Repeat this until the coil looks clean. If you just hold the button on your PV down until the coil stops smoking you will probably destroy the coil, and damage the wick. It is better to o
three or four (or more) short burns than one REALLY long one.
Tane your time. Even if it takes a dozen short bursts, it's faster than rebuilding your coil. But if you just hold the button down, trying to dry burn all the gunk off your coil all at once, you're going to NOT save any time, because you'll be spending the next 15 or 20 minutes re-building your coil...
2) turn own your voltage to the lowest setting if you are using a VV or VW PV. Using high settings is just wasting power, and again, you run the risk of overheating and damaging the coil or wick.
Try that and see how it works for you...