I had an outbreak of mites in my snake room last year, all 20 something of my snakes got them bad. I was freaking out as I never had this problem before. I took someone's advice and did the following:
1) Coat snakes in vegetable or canola oil, head to tail.
2) Place in a sterilized container. I usually left them in the container for an hour or so.
3) Remove snake from container.
4) Soak snake in water. I did this to remove the dead mite bodies and extra oil.
5) Dry with a towel, this also helps get more oil residue off.
6) Place in sterilized cage. I rinsed my tubs out and used a bleach/water mix to thoroughly clean everything.
This worked for me. All my snakes were mite free in one day. However, my snake room wasn't so easy to clean and they did get mites again. This time I followed all of the above steps but moved all my snakes into a different room. Haven't seen 1 mite since.