Snake mites ONLY come from snakes, and, rarely, other reptiles. They do not come from rodents, bedding, etc. Snake mites WILL wander long distances away from their hosts, so if you buy a bag of bedding from a pet store that's infested, you know where the mites will be? Not in the bedding--they'll be ON the bag. So when you carry it into your home, they can continue their wandering.

My recommendation is to forget trying to disinfect your aspen, because it's pointless--instead, inspect the livestock in the store you're buying from, and walk out quickly if anything has mites. They could hitch a ride on YOU.

As for mites IN bedding (such as cypress mulch)--these are generally wood mites, that are harmless to your animals. They're a different color, and you will virtually never see one on a snake, if they're in the bedding.

Another potential source of snake mites is an improperly sealed foundation. Garter snakes will get into things, including your home, and they may bring 'friends' along with them. Fortunately, the types of dangerous diseases that mites may spread in captive collections are rarely found in wild animals, so this is more of a nuisance than a huge danger.

Keep Provent-A-Mite on hand, and don't stress over it.