Some folks would call me a bit (ahem) eccentric. One of my more unusual practices is to wash my stank-ed helmet interiors with some all purpose spray cleaner (like Fantastic or Formula 409) and then a very long rinse with a garden hose. Warm water from the kitchen sink tap would work too, as long as every last bit of the soap goes away.
The sun dries them out real well.
If the sun is not playing nice, parking the helmet in front of a window fan for a day or two works well.
Heat guns - not so well.
