use provent-a-mite and follow the instructions to the letter.
apart from that, switch from your regular substrate to white paper towels, that makes it easy to keep it clean and to track the amount of dead mites.
you can give the snake a nice bath in lukewarm water. add a tiny drop of dishwashing fluid, just to break the surface tension and ensure the mites will drown.
dont use anything other than that directly on the snake, especially not toxins/insecticides, its risky and not necessary.
for cage cleaning, just the regular. hot water with diluted bleach, and then more water to remove the bleach.