I'll leave a comprehensive response to my betters on this board, but if you live in a particularly moist area, you'll want to store your mics in a cabinet or box in which you can control the humidity, ideally with some gentle air circulation, but if that is not possible, then at least with some carefully placed dessicant. Do not blow on the capsule; neither use a hair-dryer. ::--)))
I haven't been able to find a source of Silica Gel yet, but the local hardware store sells Calcium Chloride dessicants as "DriZair" and "Damp-B-Gone." Dessicants suck the excess moisture out of the air, but in doing so, they get wet -- so you don't want (for instance) to lay your condenser on top of a sack of "Damp-B-Gone."
When the dessicant becomes wet (i.e., doubles in weight), you can dry it out in the oven or microwave and reuse it, several times over.
We live in an area where the RH is probably 80% or higher year round -- it's definitely an issue here. Florida is even worse, because the high humidity is combined with heat = mold.
They call condenser microphones "condensers" because they condense the moisture out of the air. That "warm" sound is actually what your voice sounds like under water. (Sorry, I was channeling Dr. Science for a moment there -- don't believe him.)
If your microphone isn't sustaining mold growth on its capsule, it may just need some time in dry storage.
Also, although as far as I know only Electro-Voice has addressed this as an actual feature (specifically in the RE2000, which has a capsule heater), many tube mics create quite a bit of heat, which also helps to keep them dry. I tend to leave
my AT 4060 plugged in when it is not in storage just for that reason.
Don't give up on your mic!
Mark H.