Found this on a cigar forum I frequent
posted by Doug:
Mold: Do not clean the humidor! Every cigar ever manufactured has mold spores on and in it, a natural and inevitable consequence of the growing/fermenting/curing/etc. processes involved in their manufacture. Mold spores are ubiquitous in the environment as well - you inhale some with every breath you take. Cleaning a humidor in which you've found cigars with mold on them accomplishes exactly nothing in terms of eliminating the problem. Control RH and, to a lesser extent, temperature, and the mold spores that are on each and every one of your cigars already will not develop into mold. Simple as that.
Posted by Brain:
Your humidor is just a thin veneer of cedar over fiberboard. Getting it wet will probably cause damage to it. If you have a patch of mold show up on your veneer, wipe it clean with water and a towel, immediately dry it off, and then wipe it off with rubbing alcohol, and immediately dry. The alcohol may not even be necessary, but it will work as an antimicrobial that can kill off the active mold.
Doug is right. your humidor is already swarming with microbes. When you open canned goods, the microbes in the air will make them rot in no time. the thing is, you have to have proper conditions for them to grow. In the case of mold or other fungi, you need moisture and something for it to feed on. Damp veneer is perfect. Probably the best thing you could do for a mold infected humidor would be to load it with ozone, for example, stick it in a cooler with an ozone generator and run it for a day or so. That would sterilize any live organisms without harming the box.
I've received a lot of advice from the men on this forum and it always seamed
to work.