Get some Nix, get some distilled water, get a spray bottle and start spraying EVERYTHING
Dont worry, they cannot go to your family, pets, or anything like that as they are strictly snake mites.
What I was told to do and it helped a ton, is to take the boa and put him in a rubbermaid that is pre sprayed. Just put him in there with paper towl substrate and thats it. Then totally empty the tank of absolutly everything, being carefull of you have other reptiles in the house. Then start spraying the tank, the cracks, the floors around the tank, behind, on the tank, EVERYWHERE! Then every day do that once as well as spraying the rubbermaid and a light mist onto the boa's body, not the face (which isnt a big deal if it goes on). After about a week you should be problem free. On the fourth day of doing this place a water dish in the rubbermaid, but be sure to take it out while spraying.
After a week put him back in the tank with paper towl substrate, a hide, and water..thats it. Then watch for any mites, if hes clear for a month id say, then your good
Good lcuk