If you use Provent-A-Mite, leave the water bowl out for the night. If there is/was a spot you missed that didn't get completely dry and the snake crawls over that and then in the water bowl, you will be in trouble. I learned this the hard way. Cost me $150 in vet bills.
My advice is pull everything out of the cage that mites can hide in such as thermometers and anything porous. You can leave the substrate in. The time I had to deal with mites, I left the one snake with em on aspen. Then lightly spray the cage with the hides in there and cover it for about 15 mins. Then remove the cover and let it air dry for about 2 hours(can wait less but I liked to wait longer). While waiting, spray a rag down with PAM and wipe down the top rim of the cage if its a glass tank. Also wipe down the table its on. Basically you want to create a barrier so no mites can escape. Then put the snake back in with no water bowl. Leave it until morning, then replace the water bowl. Do this with any other cages. If they are PVC cages, use the rag to wipe down the outsides around the vent holes and the doors. And again try and create a barrier to keep any from getting in the cages. One treatment was enough for me for my other cages. The snake who had the mites, I did the above once a week for 4 weeks. Then on the 5th week, I threw out all the aspen and washed the cage outside along with the hides.
Any plants or thermometer, you will want to seal in zip lock bags and leave them sit in your garage for a month before using them. You also hit them with a shot of PAM inside the zip lock and seal it.
And when I talked to Bob about the stuff, he said PAM will stay active for months. They had to say 2-4 weeks because that's what the EPA made them put based on the tests being done on an outdoor sand pit for Komodo Dragons. He said the stuff indoors will stay active for a month at least. I also wipe down the outside of all my cages usually every 2 months with it sprayed on a rag as preventative per what Bob told me incase of unwanted hitchhikers.