8 inch Salt and Pepper Grinders- White and Black

I indicated that the Grinders are USED. Actually they don't seem to be used at all, but the white Salt Grinder is slightly dirty or stained on the outside from something black, maybe Pepper. I quickly tried washing it off with a wet towel and got much of the dirt or stain off, but not all. The marks will take some rubbing to remove it it seem.