Abstract: A feedstock includes feedstock paper and non-paper material. The feedstock paper includes lignin and cellulose. A method includes cooking the feedstock in cooking liquor to dissolve at least a portion of the lignin from the feedstock paper and to at least partially dissolve the non-paper material in the cooking liquor, thereby yielding a cooked pulp. The method further includes washing the cooked pulp to yield washed pulp and spent cooking liquor, regenerating the spent cooking liquor to yield regenerated cooking liquor, and bleaching the washed pulp.