Do not, I repeat, do not spray the snake. You will kill it.
- You remove the snake from the enclosure.
- Remove all decorations
- Vacuum out all of the current substrate
- Lightly spray the enclosure.
- Add new substrate.
- Lightly spray the new substrate
- Keep the enclsoure closed up for 30 minutes or so
- Open the enclosure up and let it air out until it is dry and the fumes have dissipated (several hours).
- Add your snake back in.
While your snake is waiting for his cage to dry, you can give him a bath in tepid water (78 to 82 degrees) with a few drops of dish soap in it.
While you are waiting for the cage to dry out, I'd run the water dish through the dishwasher. You can also sanitize the cage furniture either by baking it (if it's wood), running it through the dishwasher (if it's safe to do so) or if it's plastic - washing it and coating it with your mite spray.