Hi, iv'e been smoking the 510 using cartomisers for a while now, but sometimes i get this burning rubber taste coming from them, I am sure there is something i should or should not be doing, can anybody help me with this please. Also when i buy new cartomisers I get a really awful taste at first until the liquid is worked into the new one, is this normal ? is there something i should do to stop this? all help appreciated, thank you 