I always keep the humidity at 60% MINIMUM, and increase during shed, so that makes me feel better.
So I just sat in the bathroom and had my snakes crawl through paper towels, inspected every inch and I'm happy to say that they are mite free! I did one snake at a time, lol. One of them is getting pink in the belly though... time to NOT OBSESS and just keep the humidity up, fingers crossed!
I used to use moss actually, I should get some more. The bedding I use is Zoo Med... I really like it, it keeps in moisture very well. Also I'd like to add that I was using a cheap, dry bedding when my snake had a bad shed. Also, I use screen top cages on top of everything else... now I almost completely cover the cage tops with a towel, to trap humidity in, but I didn't used to do that. I learned a lot from my mistakesI leave a portion of the screen uncovered of course