People find pins, especially EM pins without mice nests in them? I say this jokingly, but seriously nests are common for most garage find type pins.

Personally, I open them up in the driveway (i.e. anywhere outside) and use a good shop vac that I keep for just such awful tasks that has a good filter installed. Suck out everything that you can and spray the inside down with your choice of cleaner, plenty of disinfecting cleaners that will kill microbes and smells but not corrode the game (don't use a bleach type cleaner).

If you are feeling extra careful, use the vacuum to suck up a 5 gallon bucket of water with some bleach in it before you empty out the vacuum. That should kill everything and make sure it is not dusty when you go to dump the vacuum out or when you go to store it. (This one poor shop vac that I use to clean up pins has had an awful life, sucking up raw sewage after a back-up in the line comes to mind as one job it did.)