I don't use coffee filter for coffee but I use them for dusting, cleaning mirrors, windows, layering cookies in a tin or plate, I let one absorb the grease floating on top of soups/stews, microwave, and so many more uses. The big size ones you can find at Sam's or Cosco are great. I keep a package of small, regular, and industrial size.
This will be a great demo for guild so thanks for posting!