This post deals with Cigar Bloom and Cigar Mold.
Bloom refers to the slow rising of "essential oils" to the surface of a cigar. It first shows up as tiny (almost microscopic) crystals on the surface, and can eventually make a cigar look slightly "dusty" with a whitish finish on the surface. It's harmless; in fact, some prefer to see a little bloom as an indication of strong taste. (Partagas anyone?)
Mold, however, is a fungus, growing on overly humidified cigars. You will recognize it as white, gray, or blue-green "fuzzy patches," with a definite dimension to them. Mold spreads by spores, so it's important to get rid of any moldy cigars immediately, before they contaminate your other cigars or the mold gets into the wood of your humidor. Mold appears when the humidity passes 85 percent. Hence the importance of keeping your cigars at the correct humidity. Something our own Awesome Humidor Solution does very well!
Saving the moldy cigars is going to be tough. Wipe off the contaminated cigars (contaminated ones only! Don't spread the mold!) with a clean paper towel, slightly moistened with distilled water. Separate the contaminated cigars from the others.
Make some kind of temporary humidor for those contaminated ones (Tupperware works well), and put it in the refrigerator. Refrigeration will dry them out without a source of humidity. After some time (depends on the effected cigar and amount of mold) the mold should be gone. Re-humidify them as you would new cigars (ie for about a week - month). Make sure you do this in a separate container. If using the same Tupperware container make sure you give it a very good wash first.
I haven't had any moldy cigars, however have opened some cigars to see them with the white and fluffy patches. The first time you may freak out a bit, however this is perfectly normal (the freaking out that is) as the fluff seems to be an unnatural addition to a nice cigar.