Our grandmothers were firm believers in reusing or repurposing everything they could. It wasn’t just about saving money—they prided themselves on finding clever uses for things. Eggshells are a perfect example: they may seem like trash, but they’re really a kitchen scrap you can reuse with a little know-how like grandma had.
Now, grandma didn’t have to worry about industrial chicken farms and food safety. We do. So, to make sure eggshells are safe for use, rinse away all the residue then scatter them in a single layer on a baking sheet and bake at 200°F or 93°C for 10 minutes to eliminate bacteria. After that, you can stash them however you want. To make a powder, grind them in your food processor or blender.
1. Crayon rehab.
Make new crayons out of broken ones by melting them in eggshells nestled in a muffin pan. Add crumpled foil to prop the shells upright and put a few pieces of broken, paperless crayon into each one. Bake in a 200°F oven for 10-15 minutes to melt the wax then let them completely cool. Once you peel away the shell, you’ve got a brand new Crayon.
2. Make smoother coffee.
Adding crushed, clean eggshells to your coffee grounds acts as an extra filter, reducing the sediment that winds up in your cup. Eggshells are also alkaline, so they neutralize some of the acids in your coffee to create a mellower, smoother cup of joe.
3. Perk up your pup.
Eggshells are about 95% calcium carbonate. One teaspoon of eggshell powder can provide about 800 to 1,000 mg of calcium, and is helpful for bone and muscle health. Adding 1/2 teaspoon of crushed or powdered eggshells for each pound of food is provides your dog with an important calcium boost, especially if you’re feeding a homemade diet.
4. Prevent garden pests.
Are snails and slugs causing trouble in your garden? Use crushed eggshells to protect your plants. The sharp edges of the shells act as a deterrent, keeping snails and slugs at bay. Plus, the eggshells provide a calcium-rich fertilizer that can benefit your tomatoes, berries, and cruciferous vegetable plants.
5. Seed starter.
Get seedlings off to a great start filling eggshells with a soil-free mix. Plant your seeds, mist with water, and keep them moist. As your seedlings grow and develop true leaves, you can transplant them directly into your garden. The eggshells will provided added nutrients.
6. Safe feeder cleaning.
Cleaning your hummingbird feeder is important, but you should never use bleach or dish soap, since these can harm the birds. Instead, empty the feeder, add crushed eggshells, and fill it halfway with hot water. Give it a vigorous shake so the eggshells scour the container to remove mold and residue. Dump out the contents and rinse it again so it’s ready for use.
7. Water bottle washing.
Use eggshells to help scour the inside of water bottles and thermoses too narrow for your hand. Simply fill the bottle halfway with water, add some crushed eggshells and a drop of liquid dish soap, then closet it up and shake. Dump and repeat if needed, then rinse it thoroughly before use.
8. Pot scrubber.
This is one of my favorite uses! Keep a bowl of crushed eggshells around to use a scouring powder. Sprinkle them into damp stainless steel or cast iron pans and scrub with a soapy washcloth to get rid of stubborn, cooked-on food.
9. Textured art.
Engage your children in a fun and creative activity by making textured paint. Mix clean, dry crushed eggshells with tempura or acrylic paint. Let the kids use this paint to add unique textures to popsicle sticks, old paint stirrers, or sheets of construction paper.
10. Treat mosquito bites.
Leave clean, crushed eggshells in a closed jar of vinegar for around four days. The vinegar will dissolve the shells, leaving you with a liquid you can strain and apply to itchy bites. Stash it in the fridge for added relief, and make a new batch every month or two.