Many things are tossed into the garbage can when they still have lots of good life left in them. Use It Up will be a section on how to use this "trash" to make new, useful items for your home. I'll try to give a variety of projects so that you'll find some that are useful for you.
This time of year, we go through a lot of eggs. Since we like to avoid sending things to the landfill unnecessarily, I've been looking for ways to use them up around the house and gardens. I generally compost them, but there are lots of other practical ways to use them up.
Compost them. The high-calcium egg shells are perfect for composting. Don't rinse them out, as the membrane contains a fair amount or organic matter. Crunch them up before adding them. Powder them before adding to worm bins.
Use as a soil amendment for the garden or for houseplants. Blossom end rot in tomatoes, eggplant or peppers is caused by a calcium deficiency, so a healthy handful of crushed egg shells will go a long way in prevention. Tip-burn in cabbages can also be caused by low calcium. For houseplants, soak egg shells in water for several days, then use to water the plants to give them a little boost. You could also use the water used to hard boil water to water house or garden plants (after it cools, of course)
Apparently deer hate the smell of them and will leave your garden alone if there are egg shells lying around the beds (being in the city, I don't have enough of a deer problem to properly test this). Leave roughly crushed eggshells lying all over the soil so that cats will not walk through your garden (and hopefully not do anything else!). As they break down, they will also increase the calcium in your soil. After some reading, I discovered that the traditional wisdom of egg shells murdering slugs is a myth!
Some people use them as seed starting containers and then plant the whole thing. I personally haven't had luck with this, but that doesn't mean it isn't worth a try.
Feed to chickens/ducks/geese as a calcium supplement. Dry them in a slow oven for a few hours, then crunch them up well. You don't want the shells to look like egg shells, lest the poultry attack their own eggs.
You can also add some crushed egg shells to a dish near your bird feeders to give the wild birds the same supplement.
Use as an scouring powder for cleaning pots and pans. Place egg shells and water in stained thermoses or coffee mugs. Allow to soak overnight, swish around for a bit, then wash as usual.
Throw some down the garbage disposal to sharpen the blades. You could also chuck some egg shells and water into the blender and run to sharpen dull blender blades. Then dump the contents of the blender on the garden, houseplants or compost bin.
Keep a couple egg shells with membrane in the kitchen strainer to catch more particulate from going down the drain.
Use to make a bathtub or tile scrub.
Use to make side walk chalk for the kids!
When you are cracking eggs, if a bit of shell falls in, use a large piece of shell to fish it out. This was the quickest way to remove those little pieces when I was a baker (and would sometimes crack a hundred eggs in a day).
Add to the mix when making stock to up the calcium levels. I don't bother to remove the membrane or rinse out egg residue. I'll be cooking my stock down for 8-24 hours, so I'm sure any pathogens will be dead. I compost them with the plant material after straining (some people don't think it prudent to compost anything with a hint of "animal" to it, but I haven't had an issue).
Soak egg shells in vinegar for several weeks, then strain and use the resulting high-calcium vinegar just as you would regular vinegar. This vinegar can also be applied to irritated or itchy skin. It can also be applied to bug bites.
You can also boil the eggshells in water (or save water from boiling eggs) to use in place of regular water for a bit of a calcium boost. Just use in recipes as normal.
Add to your coffee grounds before brewing. This makes the coffee less bitter, and then together can be used in the garden.
Add to your water kefir to give them their daily multivitamin. Kefir grains will break down the egg shell over several days, leaving behind a pretty gross looking membrane, but all of those minerals will now keep your kefir strong and healthy and the resulting beverage will be better for you. I have found that my grains would reproduce more when fed egg shells regularly.
Make a powdered supplement. Dry the egg shells in a low oven for a few hours. Powder in a coffee grinder or blender. Make as fine a powder as possible. You can put in gel caps, or mix into smoothies or recipes. It will be a bit gritty, so take that into consideration when deciding how to use it.
This supplement can also be given to pets.
Mix with egg white and use as a face mask.
Apply the membrane to torn cuticles to aid in healing.
Powdered egg shell can be used as an exfoliant for hands, feet and knees.
Cover cuts with the membrane and wrap to aid healing.
Place the membrane over pimples to bring them to a head or over splinters to draw them to the surface.
Place the membrane over a broken blister.
Do you have any other ways to use up egg shells? Comment below and I'll update the list (giving you credit, of course).