You should save your eggshells. Here's why

Everybody knows that in order to make an omelet you have to break a few eggs (perhaps more than a few, if you're trying to nail that perfect Julia Child 14-second French omelette), but what do you do with the shells once you've cracked them? If you're like most people, you probably just toss them in the trash without giving it a second thought (hopefully not down the drain, though, since eggshells can really mess up the garbage disposal).

What you really should be doing is saving them and then putting them to use. Eggshells, after all, consist of a hard outer layer of calcium carbonate with a thin inner membrane made up of protein — lots of good stuff that can be put to better use in your home and garden than in a landfill. Eggshells can be used in pet food, or even human food (yes, they can actually be edible, who knew?), they're also great for the garden, and can even be used in DIY beauty products or for decorative purposes. Here are all the ways you can repurpose your discarded eggshells.

Eggshells can be recycled via your chickens

This is perhaps the neatest, most satisfying way to directly recycle your eggshells, although it's only bound to be of use if you've got your own backyard chickens. Have you ever thought about just how much calcium it requires for a hen to create an entire eggshell (complete with egg) inside her body every single day? Quite a lot, it seems. Most poultry farmers supplement their fowls' diet with a calcium supplement made from oyster shells, but Grit shares the fact that simply saving, crushing, and mixing the shells from chickens' own eggs back into their feed serves the same purpose in an extra-economical way.

Eggshells are also healthy for dogs

If you're concerned about your doggo's diet, you may have gone to the length of making them homemade treats or even an entire homemade doggy diet, but there's one thing their meals could be missing — calcium. Luckily, there's an easy, all-natural fix for that. Incorporate some eggs into your DIY dog chow, but save the shells. Sterilize them in boiling water for a minute or two, then dry them thoroughly and crush them into powder. The Nest suggests sprinkling about half a teaspoon over each single serving of homemade dog food. The Daily Puppy also suggests that dogs can be given entire hard-boiled eggs to eat, shells and all, although you may need to break open these eggs if your dog seems confused by the shell.

Eggshells can be used in people food, too

In need of a daily calcium supplement? Why not make your own? Yes, you can do it quite easily. Grit offers several suggestions for how you can add eggshells to your own diet. The first way is to dry them and grind them into powder — they suggest sterilizing by baking them in the oven (350 degrees for 6 to 8 minutes), which will also serve to dry them out. Once they've cooled off a bit, crush them in a coffee grinder or using a mortar and pestle, then add half a teaspoon to a glass of OJ or other liquid. If you're squeamish about little gritty bits, just scoop the same amount into a gel capsule and swallow.

You could also rinse your eggshells, cover them in vinegar, and let this mixture soak for 2 weeks before straining. By this time the vinegar will have absorbed most of the calcium and can be used in salad dressings or other dishes for an extra nutrient boost.

Eggshells are great in the garden

Grit notes a number of ways in which eggshells can be beneficial to plant life. If you crush eggshells and sprinkle them around the base of your plants, the calcium carbonate they contain will enrich the soil. This is especially beneficial for vegetables such as cucumbers and tomatoes, as it prevents the dreaded blossom end rot (which sounds like a Powerpuff Girl gone bad, but is evidently some kind of plant disease). A ring of crushed eggshells can also protect any plant against slugs since they don't like dragging their slimy little bodies over those jagged edges. Half eggshells also make cute mini-cups to start your seedlings in, and when it's planting time you can just pop the whole thing, shell and all, right into the ground.

Eggshells are good for your skin

Beauty Glimpse recommends eggshells as a beauty booster. They say you can crush eggshells into powder, then mix a pinch of these with a beaten egg white and spread it all over your face for a tightening, brightening mask. Let the egg mix dry, then rinse with cold water for a healthy, youthful glow. (Wondering what to do with that leftover yolk? Try this quick and easy single-serve crème brûlée.)

You can also soak crushed eggshells in apple cider vinegar (the backbone of many home remedies) for 4 or 5 days, then apply this calcium-fortified vinegar to any skin rashes or inflammation (although avoiding any actual broken skin because, vinegar, ouch). The calcium/ACV solution is said to be very soothing to irritated skin.

Eggshells can be ornamental

If you don't mind your egg coming out of the shell pre-scrambled, you can always empty the shells via the technique known as "blowing". Poultry Keeper instructs you to poke a tiny hole in the smaller (pointed) end of a raw egg, then make a slightly larger hole in the other end. Insert a thin stick (clean, unbent paper clip, satay skewer, plastic coffee stirrer) into the egg and stir up the inside so as to break the yolk. Blow into the small hole while holding the egg over a bowl and keep on blowing until all the egg is out of the shell. Squirt some water into the now-empty shell using a bulb or other small syringe, then swish it around to clean out the egg before emptying out the water.

Let the egg dry, then paint or decorate it (carefully! it's very fragile) any way you like to make a lovely egg-shaped ornament. Use one of the end holes to attach a loop of ribbon, then you can hang these on the Christmas tree — or why not make an Easter egg tree using branches of forsythia or a similar flowering shrub?