+1 to Albert. The local chain stores are pretty good on their reptile supplies despite their normal horrible husbandry of their inhouse animals. Get some relief spray and get them on paper towel in plastic tubs with only a hide and water bowl. This makes it very easy to monitor the animals and gives the mites fewer placed to lay eggs. Also get provent-a-mite and spray down everything in the vicinity. Allow it to fully dry on surfaces that your snakes can come in contact with. The sooner you start this the better off you will be.