This design is so embarrassingly simple that I didn't think of publishing it at first. But it solves an irritating everyday problem. Pepper mill owner knows this - pepper mills spread flakes of pepper everywhere you put them. It's a "can't live without them - can't live with them" situation. When I searched for "pepper mill coaster" on Thingieverse there was no results. So here we go, and maybe this can show curious people that 3D printing can also be used for practical everyday stuff.