I just got done with mites. I did three things.
Took snake out of tub, put in container to soak. I don't normally soak most snakes, and this doesn't do anything long term, but it does kill some of the mites, and it gives me a somewhat useful place to put the snake while I'm doing the next step...
While snake is soaking, changed bedding, sprayed enclosure and new bedding with Provent-A-Mite. This prepares the enclosure to kill any eggs that the snake might be carrying or were in the enclosure.
Step three, took snake out of soaking, sprayed him with Reptile Spray and wiped the snake down.
Mites gone, have not come back.