What I do is make a concentrate, and this can be diluted down and used as a (non smelly) foliar spray. I use the 2 litre empty milk bottles, but you could use whatever size you want. You will need two of whatever size you go with.
Comparative Nutritional Analysis of Comfrey, compost and manure
Material % Water Nitrogen(N) Phosphorus (P) Potash (K Carbon/nitrogen ratio
Manure 76 0.64 0.23 0.32 14-1
Comfrey 75 0.74 0.24 1.19 9.8-1
Compost 76 0.50 0.27 0.81 10-1
I hope you are growing comfrey - it truly is the best investment - you get multiple plants growing from one plant, (just separate out the plants as they grow alongside the mother plant) and continuous fertilizer being made.