Well I spot cleaned my rack today and sprayed down the paper towels that were dried out (all of them LOL). I found one tub with two mites OH NO! Looks like those little buggers are persistant. I decided to go to the dark side and ordered a couple cans of Provent a Mite. I'm planning on spraying some paper towels, letting them dry, and putting them under the tubs in my rack between the levels. That way they are not in direct contact with the snakes. If mites crawl through my rack they should crawl over those PAM paper towels. I'm guessing the PAM will last longer, if they are in the tubs the PAM would be in contact with the snakes, and if the snake spills his water I'll have to replace the PAM paper towels. Not so if they are not in the tubs.
I actually spray down the tubs with reptile spray, wipe them so the reptile spray is in contact with all surfaces, let it air dry and then wipe them out with water. I only wipe down my snakes if I see mites on the snake.