What I would suggest is first keep them as far as you can from your collection,next make sure you completely clean their separate enclosures, I say seperate due to you saying they were housed together. I use a small amount of bleach to water mix to completely clean their enclosures and make sure you totally rince away any bleach residue left allow to dry completely then use PAM Provent a mite spray and follow the directions completely allow this to dry. While you are cleaning the enclosures you can soak the snake in a solution of mild dish washing liquid and warm water this should kill some of the mites on the snakes. Then as said above replace the snakes into their enclosures and repeat a week later or so if a second infestation comes about. Hope this helps.