I grow heirloom comfrey in my garden. It was given to me by my sister, who had received the original plant from our grandfather. I never really know what to do with the comfrey. It is one of those herbs that has mixed reviews of whether it is safe or dangerous. This year I think I have found the perfect use.
According to the website, Care2 (link below post) comfrey does not draw nitrogen from the soil as it decomposes. Comfrey also decomposes quickly and helps activate the heat/decomposition in your composter. For full information visit Care2 site to read entire article.
Soaking the comfrey in boiling water.
My compost bin