We've used these Ikea Intressant spice mills🧂a lot over the last few years in the kitchen, but dunes of pepper and salt fall below when you put them down. Putting drinking coasters below had been a quick but still messy fix. 

I eventually decided to create caps that hug the mill and nest them in a simple base. The counter is now 🤌 

The caps have slots for removal flexibility. One of the caps and base sides have a circle cut-out for tactile differentiation from the other cap.

For anyone who wants to attempt these on other mills, the diameter is 66mm, so scale from there as needed and test with one at first.