Hit them with the one two combo! Provent-a-mite can be sprayed on the bedding and in the tank and the residual will continue to kill mites for a month. Follow the directions closely!
Reptile Relief can be used on the animal to kill any that are actually on the animal at the time.
Some people I have talked to will soak a snake first to drown the mites on the snake and to force out any that are hiding in the scutes and then use the Reptile Relief. Just follow directions closely!