Mom used her old one to wash black walnut oil off after dad ran the outer husk off with the car in the gravel driveway...works.
I didn’t know that walnut stain would ever come off. A squirrel brought in a walnut and hopped up on my outside table
on the patio and I had beige rubbery place mats and that
squirrel took that hull off on the place mat and there’s still some stain on it. I soaked it in hot soapy water and use a little brush on it and you can still see the stain a little. Sure was a mannerly squirrel, keeping his food on
the place mat....LOL!