First off you should always Quarantine new additions. Many people speculate on the amount of time but that is always up to the individual.

As far as other things to do this is what I do and it has worked for me once, thankfully and I have not had to do it again.

1.) Pick yourself up some provent-a-mite. Follow the directions and do exactly as it says to treat the contaminated area.

2.) Before I treat the area I will soak the snake in a mixture of betadine and water. Mix with water until it is like a light urine color.
Helps drown mites and Betadine solution will help with any of the areas the mites have been biting.

3.) While the snake is soaking I will treat the enclosure and surrounding area with the Provent-a-Mite. And allow to dry for quite some time before reintroducing the snake. (A LONG TIME...)
I also spray exterior areas and the rack along with the floor surrounding the whole area that is infected.

4.) Before I replace the snake into the Treated area I will spray the snake with (reptile relief) and allow to soak for a while helping to relieve any stubborn mites that may still be holding on. You can also run the snake through your hands to get the Reptile relief into the less accessible areas a little easier.

5.) Replace snake to enclosure with just Paper towels and keep a constant Eye out daily for any new mites wondering around I usually do this routine weekly until I see Zero mites anywhere. If you dont get them all, it will only be a matter of time before they are back in full force. I have also removed all living creatures and bombed my home before to kill any chance of their return. Just insure your snakes are free of them before this as if not they are gonna come back in full swing. And insure you wash everything really well including all things related to housing feeding and after bombing if you choose to do this.

I am sure others will post with there methods but this is mine so I hope it will help you out and good LUCK...

J