Madder root; how to

[richsc]

So I bought a bag of madder root, but the store sold it without any directions on how to make it. Do you soak it overnight in water to extract the dye? Powder it and put it in with the wool/linen? I can't find a recipe, so if anyone has it many thanks! <p>Legio XX<br>
Caupona Asellinae</p><i></i>