Folk recipe (quite imprecise!)
I gather five to seven large comfrey leaves - a big handful.
I let them wilt overnight - I lay them out flat, not touching, on a clean towel.
Next day, I warm up - in a double-boiler - a quart of the best olive oil I can get ahold of. Warm it up to about 100 degrees or so.
I place the leaves into the oil, and keep the heat on low under the double boiler for about 20 minutes.
I lift the lid and let the steam out. Once or twice after that, I lift the lid again, and if there is condensation, I wipe that off (trying to get as much water out as possible).
Then I let the oil and comfrey sit again till next day.
I strain the leaves out of the oil. The oil now looks nice and golden green. I compost the leaves.
I add about 400 units of vitamin E by squeezing a vitamin E gelcap into the oil and stir it in. I am told this is a natural preservative as well as good for ya.
The oil can be reheated, and beeswax added to make salve, or can be stored in a glass jar in the frij.
For adding beeswax, I add it half an ounce at a time till it's the right thickness. To test, I put a little salve in a spoon, set the spoon in the freezer and wait a few minutes.
If it comes out too thick, more comfrey oil can be added. Too thin, more beeswax can be added. It just needs to be heated up and stirred.