I did a three part series on how to make comfrey tincture in August. It is hard to make, but too expensive to buy, so I make it, ROFLOL!
I would be happy to walk you through it, if you decide to try. :) Here is the link to the how too:
Just a little light reading. Let me know if you have questions.
Enjoy decocting the comfrey roots!
:D