Hey Chad,
I got off work, came home and was working on my breeders, cleaning, weighing etc.
Frank and Jeff were also giving you good info. Just treating the enclosure (for a full blown outbreak) may not be enough and you could have a re-infestation. Preggo mites will travel and if they lay their eggs away from the cage, does not matter how much you clean the cage, the eggs away from the cage are safe from your extermination efforts. I've had mites twice in the last year. Both times was on a new acquisition and both times I had pretreated the cage PRIOR to their arrival. In other words, no preggo mites escaped, since they had to cross the killing zone.
So for me in both circumstances, that ounce of prevention was all it took.
For your situation, I would still recommend Provent-A-Mite since it's the only product I have experience with and it worked both times. It's used to treat the cage, so any buggers that go out for a stroll, come in contact with it and die. (insert evil grin here) For you I would also treat the area around the cage to keep any mites that may be out from getting back in alive. With a few weeks of weekly treatments, you should be OK.
As with any chemical, READ the directions, it is NOT to be sprayed on the snake and is NOT to come in contact with the water bowl.
Keep us posted on your progress and good luck.
P.S. I remember you mentioned they may have come from another snake? Might want to treat all of your cages at once. Just in case some buggers have made the pilgramage to the "new" all you can eat buffet.
P.P.S. I'm off to get dinner, will log back on when I return. Frank and Jeff really are good guys and were only trying to help.
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Thanks,
Dave Colling

www.rainbows-r-us-reptiles.com
0.1 Wife (WC and still very fiesty)
0.2 kids (CBB, a big part of our selective breeding program)
LOL, to many snakes to list, last count:
19.29 BRB
13.18 BCI
And those are only the breeders 
lots.lots.lots feeder mice and rats 