there are quite a few ways to get rid and quite a few products on the market.
But the one key factor with all methods is cleanliness.. When I have had them I have found daily scrubbing the viv with houshold detergant or bleach almost eradicates all of them then you just have to kill the ones on the snakes.
For this I use a product called 'frontline' it is an alchohol based mite killer that I get from the vets over heere in the UK. I use this as its easy for me to get hold of - a method I would prefer to try is using 'predetary mites' (another type of mite that live off the first mites and die once they are gone) but by the time you have noticed mites I have found it takes too long to order them and recieve them - again this may be easier in the US. I have heard vegatable oil been used but not too sure on this method - obviously the snake cannot be in too much heat whilst using this method and sounds too stressfull for my snakes to go through.
Hope my opinions help
Sam