Are you talking about oil? Hash oil? Honey oil? If so, look under harvesting and curing. I am pretty sure there are some threads in there about it. You can also try the search function and probably come up with some hits on this topic.
Your thread name caught my attention as I was logging in just now . . . because if you mean hash oil, I love that stuff.
I know that there are a lot of people who swear by the butane method, but I am too chicken to try it. I use the isopropyl alcohol method instead.