COLD PURGING
Other than the unfortunate circumstance of having to step away from a cigar for an extended period a' time, a case can be made that there's never a better time to purge than immediately up-on a cigar's toasting/lighting. I mean, think of the charring, gentlepersons. Thusly, a perfect time to cold purge is prior to yer first hot draws. Simply blow out through the cigar in a couple/few shortish exhalations, then commence in the smoking.
I've already mentioned putting down a cigar. Yer half-way through the thing and the wife wants the both of ya to go to the mall? I'd recommend d-i-v-o-r-c-e, but whom can afford that? Instead, roll the ash off and purge as described above. Leave the thing outside under an awning or such, then come back to it later... the cigar, not the wife. You'll only lose about 10% of the loveliness; as opposed to 50% of yer belongings.
Whenst re-lighting, remember to follow the same protocol as lighting -- toast, light, purge.
HOT PURGING
We've all smoked cigars that turn unpleasant. Whether it's the usual bitterness, the less usual sourness, or just a mottling of once delineated notes. Gentlepersons, I give ya the hot purge. Simply hold the flame of yer opting to the char and blow in the same manner as above. Perhaps tick longer in each blow.
You'll note that the flame will become a multi-colored thing -- continue till it ain't. That's ammonia and other nastinesses being burnt off. You'll also, hot or cold, be pushing any build-up a' tar down the shaft and aways from the ol' smoke-hole.
HOW OFTEN SHOULD I PURGE?
It's really up to you. The cello is breathable and won't hurt yer cigars. Might even protect them. Although I would say take 'em off if you're planning on aging. Oh. Right answer, wrong question.
As to hot purging: if it ain't broke, don't fix it.
As to cold purging: after lighting, if ya recall to.
Also, that's mold -- not plume. Also, also, that's a real Cuban. It's just a fake Cohiba.
SOMETHING ELSE
Some folks don't purge at all. I do.
None of us is wrong. I'm just more right.