I've started taking yoga, to help with toning, flexibility, and general relaxation. Plus, I've heard it's great for cycling. In any case, I dragged out my old yoga mat and took it to class. When we were doing upward dog, I put my face in the mat and noticed a less than fresh smell. Ewww... Does anyone have any advice as to how to clean a yoga mat without buying a ten dollar bottle of "mat wash"?