On different occasions, I have worked with walnut oil, sunflower, and sesame - all are cold-pressed, unrefined. Three drops of oil of oregano or grapefruit seed extract in a tablespoon of your oil of preference adds a little something extra. Also, some OP'ers are pulling with cold-pressed hemp oil (label says no THC), others with grapeseed oil, some like extra virgin coconut oil, and some pull with hexane-free, cold-pressed castor oil. Dont't use canola oil; you can read some posts about that.
Dr. Karach says the results are not as good with EVOO, but a few said they are using it and say they are seeing good results. I tried Extra-Virgin Olive-Oil a couple of times but did not feel anything. For me, there was no change in the oil's texture or color at the end of the 20 minute pull. Extra-Virgin Olive-Oil with lemon juice and garlic on a salad is one thing, but truthfully I felt the heaviness of the oil when I tried pulling.
I suggest you start with sunflower oil because it is light in flavor and texture, and every post I have read says during the OP session the oil changed to the milky white, watery consistency it should reach. Read the description on our oilpulling forum //www.curezone.org/forums/description.asp?f=738
about how to do this.
Don't expect overnight miracles. It is perhaps the safest and simplest procedure and helps a host of problems. Just start pulling - Let us know how you progress.