Well that first thing that you would need to do is order a can of PAM (Provent a Mite NOT the non-stick cooking spray)
http://lllreptile.com/store/catalog/...rovent-a-mite/
The next thing that you should do is remove the substrate that you are currently using, and replace it with white paper towels. There are 2 reasons for this:
1. The white paper towels make spotting the tiny black buggers
2. mites can hide in the most other substrates which will prolong the infestation.
Remove as much as possible from the cage. If you are using things like half log hides (which I don't recommend) They will need to be either baked in the oven or thrown away (personally I would just toss them and pick up some better hides)
You should soak your BP 2 times a day in warm water with a drop or two of Dawn dish soap. This will help to remove the mites from the snake.
Follow the directions on the can of PAM to the letter. This stuff is nasty, in high enough concentrations it will drop a full grown man.
Change the water out frequently as BP's tend to soak to try to get the mites off of them.