I say soak the snake in a mite bath, and every time you change the bedding treat the bedding with provent-a-mite, quite possibily the greatest product ever.

If there are mites on one of your snakes, there's mites on all of your snakes.
Treat em all, and do it more than once. When you clean the stuff from the housing, make sure it's completely submerged in water, sneaky little bastards will survive even if a small part of your hiding box is above the water.

Provent a mite once a month, but make sure it's completely dry in the cage before you put the snake back in, i usually wait an hour, and if you get any on the glass wipe it off right away.

Also, when you bring new snakes home, don't even wait, give em a mite bath right away and provent the cage.