Is there a trick to cleaning the heads when using 100%vg? Ive rinsed them in hot water and its been fine with pg/vg mix, but with vg when i use a head thats been cleaned it tastes kinda like a dry burned wick. New heads are great taste good for quit awhile with a new one. Ive heard to dry burn, but tried and it burnt the wick. Any Thoughts would be greatly appreciated! Thanx