The way I deal with mites is with PRovent a Mite...I spray all cages with it (with animal and waterbowl removed, and the hides) Let it dry, then place in paper towel, hides and snake, and water bowl. I repeat the treatment every month for 2-3 months, more if necessary (I only needed to do it for three months, haven't seen any mite since, and its been over 5 years).
Every new animal gets placed into a cage that has been treated with Provent a Mite. As I live in a small one bedroom apartment, very hard to complete quarantine any new snake, but I do my best by keeping my new additions in a different room.
I breed my own rodents and I don't buy my shavings at the same place I buy my snakes. (mostly due to it being far cheaper to buy a huge bag of aspen at the feed/seed store than it is to buy the same size bag at a pet store (even if they carried it.) or even the reptile show (its a few bucks more).
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PHLdyPayne