I have both a Far Infrared Sauna and an ozone sauna that are both excellent for detox, but in different ways. What I have found with the ozone sauna is that I get a rash when I have saunas too close together. My understanding is that my detox pathways are blocked and I have to wait until the rash clears up before I do another ozone sauna. If I help my detoxing with pectasol, then I don't get the rash. I have had a rash for two weeks. The spots on the white towel are left by almost everyone who uses the ozone sauna, including me. I know that others have had the spots tested at Doctor's Data and the results came back positive for heavy metals. I am curious about the yellow staining that is also left on the towel by some, but not all people who use my sauna. I have read that is caused by someone who smokes. I haven't smoked for 50 years. It will be interesting to research more.