Eggshells have many practical uses for growing plants, cleaning utensils, etc. So, don't rush to throw away leftover eggshells.

Seedling nursery
You can use half of the eggshells (after washing, take the whites, fry the yolks) to grow plant seeds, which is very useful. Remember to make a small hole in the bottom to help drain water before pouring soil and putting the seeds in the eggshells. After the seeds germinate, you just need to bury the shells in the soil, the minerals in the shells help the plants to be greener.
''Calcium rice''
Eggshells contain a lot of calcium and minerals. Therefore, you can wash the eggshells and then fry them in a pan until crispy, then pound or grind them finely. Sprinkling a little eggshell powder into your pet's food will help increase their nutrition.
Remove grease stains from bottles
Crush the eggshells and put them in a bottle or jar with a small neck that is difficult to clean. Then, fill it with water and seal it for 1-2 days. Rinse it vigorously several times to effectively remove stains and grease.
Using eggshells as fertilizer for plants

Eggshells contain many nutrients such as phosphate, magnesium, potassium, and iron, so they can be used as very good fertilizer for plants. You can crush raw or cooked eggshells and mix them with potting soil or compost.
Ants
Roast or burn the eggshells until they are dry and turn yellow, then crush them and sprinkle them on the corners of the walls where ants often visit. The strong scent from the eggshells will quickly drive the ants away.
Clean blender blades with eggshells

You can clean your blender by putting eggshells and warm water into the blender and turning it on. The protease (from eggshells) has strong cleaning properties that will help clean the blades.
Remove stains from clothes
Wash the eggshells, crush or crush them, then put them in a cloth bag and tie it tightly. Put the cloth bag containing the eggshells and clothes with stains or yellow stains that are difficult to clean into a basin of hot water for 30 minutes. Then, remove the cloth bag and wash the clothes again with soap.
Clean burnt pots and pans
Eggshells contain protease - a strong cleaning agent that can clean burnt pots and pans.
Put the crushed eggshells in a pot with a little salt. Add some water and bring to a boil, then scrub with a dishcloth to make the burnt spots come off easily.