Yes, I have heard that freezing will kill bacteria, so I will be interested in your little test.
However, even if it does kill the bacteria if you just get the holster wet the next day it seems like you’re back where you started. It would seem the strategy should be to keep the holster from getting wet to begin with.
So, does the holster touch you bare skin? If so have you considered an undershirt?
Do you have more than one carry rig that might allow you to rotate guns so the holster has time to dry completely.
The manufacturer of my holster recommends using a product called Renaissance Wax to protect the leather. This might create a protective barrier that reduces the moisture absorption.
Anyway, just some random late night thoughts – good luck.
A major source of objection to a free economy is precisely that it ... gives people what they want instead of what a particular group thinks they ought to want. Underlying most arguments against the free market is a lack of belief in freedom itself.
- Milton Friedman