Ideas for recycling used coffee filters include composting them, using them for cupcake pan liners, making drip papers for ice cream treats or using them as wine strainers. Rinse and dry the filters on a string or clothesline before using them.
Unbleached coffee filters are biodegradable and may be added to a compost bin. They can also be mulched into the garden, along with the coffee grounds, to discourage deer from eating plants.
The texture of a coffee filter is about the same as a cupcake liner, and it handles heat well. You most likely need to trim the filters before use, and it's best to bake a recipe that doesn't clash with the coffee flavor. Vanilla and chocolate cupcakes work, but citrus flavors like lemon or lime may clash.
To create a drip catcher for ice cream treats on a stick, poke the stick through the bottom of a dried coffee filter.
Coffee filters strain the grounds out of hot water, so it makes sense to use them to filter wine. Most wines don't need to be strained, but once in a while, a cork crumbles and leaves little annoying bits in the bottle. Strain the wine into a carafe to prevent you and your guests from dodging floaters while drinking. For this recycling idea, the filters must be well rinsed and thoroughly dried so the straining doesn't alter the taste of the wine.