If you search the ball forum, you'll find several post on how to deal with mites.
Here's how I have taken care of the problem when someone gave me the gift that keeps on giving. I have asthma and allergies so I cannot use Provent a Mite, etc. My procedure works and is much safer for you and the snakes.
Nix is a head lice shampoo that is available at your local drugstore. Mix about 1 ounce to a quart of water in a spray bottle. Remove your snake, dump the cage substrate, and spray the cage down with the nix solution. Let it sit for about 30 minutes. Then clean the cage and place newspaper, paper towels, or a small amount of sani chips in the cage. If you use sani chips just put in enough to barely cover the bottom of the cage. Sprinkle the Sevin dust all over the newspaper, paper towels, or sani chips. 10% strength is recommended but I use the 5% and it works fine. I also sprinkle a 1 inch wide line all the way around the snakes box or cage. This prevents them from spreading to the other cages/boxes. You could also go with a 1 inch wide line of vaseline along the inside upper edge of a reptarium/glass cage. It's just messy to clean up.
Next, spray the mix all over the snake. Return the snake to his cage. The next day if you see mites, spray the snake again. If not, I repeat this every other day for a week. The mites lay eggs under the snakes scales so you must keep this up for at least a week. Provide the snake with fresh water every couple of days but do not leave the water bowl in the cage. Snakes tend to soak when mites are irritating them and the Sevin dust could be harmful. The nix is much safer and once it dries, it stops working.
There is another step that I do as part of my quarantine process but I'm not sure if it's something you want to do with a hot. I place the snake in a box of appropriate size and add clean warm water. They tend to drink right away so this is just water. After 30 minutes I add more water with a small amount of dish soap. This breaks the water tension and lets the water get under their scales where there are mite eggs and mites in tiny air pockets. After another 30 minutes my new arrival goes to a quarantine rack. I check them daily and if I see mites they get the treatment described above.
This may seem like a lot of work but if you don't treat this serious and jump on the problem right away, multiply the work times the number of snakes you have. Mites can spread through your collection in just a couple of days.
Best of luck
John Q