What has been reported to me by a listener is to put 1” of cornmeal in a flat pan that’s large enough to get your feet in. Add enough room temperature water to wet the cornmeal. Let sit for about 2 hours. Then add enough warm water (for comfort) to cover the feet and soak. An organic  cornmeal product might be the best choice because of its fine texture. Soak feet for 1-2 hours. More than one treatment may be needed.