Whole buckwheat cushions cannot be put into the washing machine or drier. However, you can empty all the buckwheat hulls from your pillow. The cotton pillow cover can be washed and buckwheat hulls can be set in the sun to dry.
Machine wash pillow cover with cool water, air dry to avoid shrinking. Store buckwheat pillows in a cool, dry place - as you would woolens and down blankets.