I had a mite infestation once and only once. They came in on a red tailed boa that i got of kingsnake.com.
I bought some Provent a mite and sprayed his inclosure. For the actual snake i used Repti relief and spreyed a paper towl and rubed the snake down so as not to get it in his pits and eyes. During the next cleaning of all my snake cages i sprayed all the substrate and replaced the snakes. I never had a reinfestation. Provent a mite is Awesome. Nothing works like it.