I live in Southern California, so the environment is pretty dry. We only get a little mold in our shower, but I clean that with bleach.
Guess what? I put one of the pads on my chest last night instead of my foot. It's too soon to tell for sure, but I barely coughed at all today. I'm going to repeat this tonight as well. This cough has ups and downs, though, which is why it's too soon to tell if the pad helped there.