When I began the op about a month ago, walnut oil was the only other oil I had on hand besides EVOO. Extra-Virgin Olive-Oil is a little too heavy to me, and walnut oil is so mild in flavor that I thought why not until I could get to the health food store. Extra bonus is walnut oil is one of the highest in omega 3s. I felt there had to be a good exchange taking place during the swishing; in my mind it just made sense. From time to time I switch around with sesame, and sometimes I mix the oils in an op session. As the rest of you have reported in your experience, stains on my teeth have disappeared and my feet have softened. Bonus is decreased sensation of achy joints in my neck, back, and shoulders. In this short time, I have had some really nice reactions. A real head to toe improvement.