Here's a lonely egg shell sitting on the top of my compost pile. It looks like it has some coffee grinds sprinkled on it but that makes sense because my kitchen compost crock is usually full of coffee grinds (with the filters) and egg shells.
Weekend breakfast in my family of four is great for the compost bin. During the week it's we'll eat cereal or toast or something quick. But on the weekends we like to sit down and eat a hearty breakfast together. And hearty is good for creating compostables.
My wife and I will have two cups of coffee and that means 4 coffee filters full of coffee grinds. 4 filters you say? Yes, we don't use a regular coffee pot anymore. We find it easier to make each cup individually with a Melitta Cone Coffee Maker This way the second cup is as fresh as the first, even if you have it a few hours later.
And then we'll have 2 eggs each. So that's 8 egg shells in one sitting. And since I eat like piggie, let's just say that I have a few more than my share of two. Egg shells are loaded with great stuff that's good for plants. I know of lot of people who crush the shells and put them directly in their garden.
But that's more work than necessary, so I just like to toss mine in the compost bin as you can see.