Coffee filters have a multitude of uses aside from brewing your coffee. Here are some reasons to keep filters (which are super cheap) around even if you don't drink coffee.
Step 1: Liners
Coffee filters can be used to protect dishes by layering them in between your breakables. You can also line the bottom of tins and dishes OR put them between tortillas right before heating them up---this makes the tortillas come apart easier.
Step 2: Interfacing
Use as an easy tear backing for applique sewing or embroidery.
Step 3: Sprouting Seeds
Lightly wet the filter and then place the seeds you want to sprout inside. Set in plastic bag and set aside in a warm area out of direct sunlight. Check back in a few days for evidence of sprouting (if you see mold it means you either used too much water or the area was too cold).
Regular coffee filters work better than filters made for Aeropress coffee makers.
Step 4: Deodorizors
Place a couple tablespoons of salt or dried lavender inside a filter and then secure it with a rubber band or twist tie. Set in your closet, shoe boxes, fridge, etc. anywhere that might get a little stale smelling.
Step 5: Weighing Food
Place your chopped fruits, veggies, etc. in your coffee filter and set it on your scale. The coffee filter acts as an easy to use and easy to move mat.
Step 6: Seive
Use coffee filters to strain liquids.
Step 7: Pet Toys
Shred a bunch of filters for nesting material for your hamster or to add in foraging toys for your birds. They'll love pulling the strips out and playing.
Step 8: Blotters
Cut up the filters into small strips or squares and put inside your bag for a quick aid when the summer sun is making your sweat. Coffee filters soak up the oil/sweat on your face leaving you feeling refreshed.
Step 9: Spices
For cooking with spices that you don't want to bite into later (like cardamon, etc.), put all your spices into a filter and secure. This makes it easier to find and remove all those spices/flavorings you don't actually want to eat.
Step 10: Prevent Rust
Coffee filters can be used to prevent rust in your cast iron pans by placing a filter inside after washing.