I take two dozen green fruits (nuts in husks). I make a slicing cut through the husk, down to the nut, around 3/4 of the circumference. I tie them into a cheesecloth bag (easier to get rid of) then put them into a 2 gallon stock pot. Then I fill the pot with water (tap but distilled may be better). I boil them for four hours. I then remove and dispose of the fruits. Usually, at this point, I’ll continue cooking the mixture until it’s reduced by half. Then I’ll add an equal amount of denatured alcohol. I’ll let this set overnight, then bring it to a boil the following day until it is reduced by half. There’s no known science here, so you’ll have to experiment. But that’s half the fun. You have to test the dye to make sure it’s as strong as you want it to be. I went through 5 dozen walnut fruits to get about 700 ml of really strong dye (some of which I’ll use for ink). Only you can decide whether it’s worth the trouble. But it reinforces the fact that our predecessors had to work very hard. It’s a good thing they didn’t have TV. Generations of fine craftsmanship would have never occurred.