Ok, I have minimal experience as a chandler, but a lot with B&B. Like Donna I have seen fo instantly vaporize in soap also flavor oils in lip balm. My thought is if you had significant burn off in wax, aside from the vapor cloud, wouldn't there be minute bubbles as the fo deep in the wax vaporized? Although most would not be visible in opaque wax, I would think some should show up in containers on the glass.