How is hair dye made with walnut hull powder?

I worked for a natural dye mail order company for a while. The owner boiled

walnut hulls in water and combed the strained, cooled stained water through her

hair (med blonde) and it blended in the gray very nicely. I think she left it in for a while then rinsed after maybe an hour.

So if walnut hull powder is just from the same source, add a little warm water, stir, strain, comb as above I would think. Wear gloves and do not pour on skin of scalp, just comb through part you want to color with fine comb you dip in solution. Also wear

old clothes and towel around shoulders. Wipe stains on yourself with peroxide

soaked cotton ball or scrub with soap and water or both?