This listing includes 20g of organic ground walnut hulls in a recycled paper envelop. They are USDA Certified Organic.
Walnut is what's known as a substantive dye- that is, it does not need to be used with a mordant to be colourfast.
As with most natural dyes, the colours will be stronger on protein fibres such as wool or silk. Walnut on cellulose fibres like cotton and linen tend to be paler and more subdued. Synthetic fibres tend not to take up natural dyes.
Equipment and Safety
Always add powder to liquid, not liquid to powder (to prevent powder from flying everywhere). Wear gloves and an apron to avoid staining your hands and clothes. Always dye in a well ventilated area and use separate pots and utensils from your cooking pots.