I have a Corn snake that developed mites after I got her and I treated with hypoaspis mites to avoid chemicals as she had them around her eyes and nostrils, it's now been 4 weeks and she seems comletely clear and stress free. If you would like to know what I did I'd be happy to post a thread as it seems a very safe alternative to the chemical method as the mites get where you can't go with frontline and other pesticides.
I will write this up and hopefully have it posted by the weekend, I was sceptical at first but it has worked and it is natural and avoids all the complications and side effects of chemical treatments.