I have seen both the poly fill and the CE2 types advertised as "Clearomisers". You should not have to dry burn either one before using. You "can" dry burn both types to clean them after the coil starts to get gunked up. This prolongs the unit and makes it
vape better when it starts to get old.
With a poly fill type you have to disassemble the unit and remove the poly fill wrapping before dry burning. Do not attempt to dry burn these with the poly fill around the coil. This process can be a pain in the but and it's hard to get it back together good.
With the CE2 type you can take it apart (To disassemble you just gently pull the plastic tube off while the base is anchored to your
ecig. Do not pull on the center tube with ceramic coil, this can break your clearomiser.) and rinse it under running water, then dry the wicks with a paper towel and gently dry burn the unit till the coil starts to glow again burning off the gunk. Reassemble. I do this about once a week only after I start using them.