Put about a cup of freshwater and a tablespoon or two of vinegar. Shake for a minute, let dry. I usually put mine near the hot air vent (not too hot) of my heater. It didn't totally eliminate the stank, but it helped a lot.
Been using this for three years now. So good I bought a second one from Harbor Freight at a fraction of the cost. Works like a champ against long-term moisture which is the primary culprit of the whole-house stink bomb.
I have the same issue and only with my boots also. I tried soaking them in BacOut which is an enzymatic cleaner that didn't do sh!t. My boots smell like decomposing carcasses. I'm going to try letting some tea-tree oil soak in them because the stench has to be from fungi.