How do I keep my portable sauna clean?

I recently bought my second portable sauna, the type in which one sits under a tentlike structure with one's head outside the tent. My previous sauna (same design) became quite smelly and funky, and I never figured out how to clean it, or prevent it from getting so dirty in the first place. I asked the man who sold it to me, and he said- use Febreeze! I am chemical sensitive, so no, I think not. When I moved, I threw the old sauna away.

Now I have a brand new one. How do I clean it or keep it clean? The tent is made of padded silver fabric. Previously, I sat on a towel, but inevitably, my sweaty shoulders, arms and knees brushed against the interior of the sauna. Instruction to "wipe surfaces with a towel" seems futile since most surfaces are absorptive. I thought of wearing a bathrobe in the sauna, but I read several questionable things in various places:

-the far-infrared only works/or, are most effective. on unclothed skin
-wearing clothes in the sauna prevents the sweat from cooling your body, causing overheating and causing toxins to be reabsorbed by remaining in contact with the skin
- you can wear clothes in a FIR (Far-Infrared-Sauna) sauna because you don't sweat as much

Any ideas, sweaty friends?