Nifty·Posted on Aug 6, 201811 Useful Things You Probably Didn't Know You Could Do With EggshellsThey're seed starters, a great cleaning abrasive, and a calcium supplement for your pup.by Emily ShwakeBuzzFeed StaffFacebookPinterestTwitterMailLink You know you can do a lot with eggs...but do you know how much you can do with all those eggshells?! No? Well, you're about to. View this photo on Instagram instagram.com And FYI, for some of these hacks, it's important to sanitize your eggshells first! Here's how: Rinse the shells, then boil them to kill off any pathogens. Let them dry overnight, then put them in the oven for about 10 minutes to get them completely dry. 1. Fill eggshells with soil to use them as biodegradable seed starters. View this photo on Instagram instagram.com Sanitize the shells and poke tiny holes in the bottoms with a sewing needle for drainage. Then, fill the shells with soil and two or three seeds. Once the seeds have sprouted you can plant the shells directly into dirt! 2. Scour a dirty pan with a soapy sponge and crushed eggshells to make it sparkle. Angela Corbelli / Via youtube.com You don't need to sanitize the eggshells for this one, just be sure to give the pan a follow-up scrub to be safe. Learn more here. 3. Shake them up with soap and water to clean the inside of containers with narrow necks. gippslandunwrapped.com The eggshell acts as an abrasive and scrubs the parts you can't reach. Learn more here. 4. Grind up shells and sprinkle the powder in your dog's food for extra nutrients. View this photo on Instagram instagram.com Eggshells are a great source of calcium, and pups needs it as much as we do! Sanitize the shells and pulverize them in a blender or coffee grinder until they're a very fine powder without any sharp edges. Keep the powder in an airtight jar for up to two months, and give your pup about a 3/4 teaspoon per cup of food. Learn more here. 5. Or pulverize the eggshells in a blender and feed them to your tomato plants to keep them healthy. thefarmchick.com If blossom-end rot is a problem with your plants, they need calcium. Sanitize the shells, grind them up in a blender, and pour a handful in the planting hole. Learn more here. 6. Let them soak with warm water in your mugs to clean off coffee or tea stains. mamabee.com The eggshells will absorb the stains overnight. Learn more here. 7. Grow geodes in the shells with alum powder and food coloring. View this photo on Instagram instagram.com After cleaning out the shells, coat the inside with glue and alum powder, then let them dry overnight. Mix up boiling water, alum powder, and food coloring in a jar and let that sit for about 30 minutes. Drop the eggshell in and carefully push it down with a spoon until it's submerged. Leave it overnight, then in the morning pull out your geode. What a cool science project! Learn more here. 8. Crush the shells up and brew them with your coffee grounds to cut the acidity and sweeten your cup of joe. View this photo on Instagram instagram.com Sanitize the shells and crush them up, but don't grind them up too small... You don't want any steeping through into your cup! Sprinkle them into the grounds and brew as usual. Learn more here. 9. Pour candle wax inside an eggshell to make cute tea lights. View this photo on Instagram instagram.com If you want to dye the eggs, dip them in water, vinegar, and food coloring and allow them to dry upside-down. Use a tiny bit of glue to stick the wick to the bottom eggshell, then just pour the wax in like you would any other candle holder! 10. Mix eggshell powder with flour and hot water to make sidewalk chalk. View this photo on Instagram instagram.com Mix the powder of 10 eggshells with two teaspoons of flour and water and knead the dough into logs. Roll them in paper towels and leave them to dry for about three days. Learn more here. 11. Fish broken shell out of your eggs with a larger piece. food-hacks.wonderhowto.com The shell is sharp enough to cut through the egg white and easily scoop out the piece that broke off. Learn more here.