I was impatient so instead of soaking it in oil for days, I chopped the vegetable matter rather fine and added it to double boiler and brought it up to 100-110 degrees F for several hours (several times over the course of a day). I then strained the weeds out and added beeswax until it melted. I have not yet explored far enough to know if heat was a viable method for extractions or not, but it seems reasonable that a container could be placed near a cooking fire to work in a similar fashion.
Apparently I now also have a use for some of the terrible pottery I made last spring!
Note that various publications warn that both of these items can cause contact dermatitis in some individuals so testing use before liberal application is advised.