Strain the onionskins from the big dye pot and discard them, then bring the pigmented water to a boil again, and place your wet fabric or yarn in the pot. Simmer for at least an hour, stirring as needed to keep the fabric submerged. Let the fabric cool in the dye bath or, better yet, soak for a night or two.
Rinse the fabric in cool running water until the water runs clear. Hang dry, and savor the moment along with the earthy hue.
All dyed fabrics should be washed before being used in any craft.