Other Ways to Use Eggshells Eggshells can also be added to your compost pile, along with other natural waste. The minerals in eggshells will slowly dissolve and help add nutrients to your compost pile. Since eggshells take a long time to dissolve, grinding them up before adding them to your compost pile can help speed up the process. Another method is to make a nutrient water from eggshells: Wash the eggshells thoroughly. Let them dry completely. Grind them into a fine powder. Place the powder in a glass or container and pour boiling water over them. Stir the mixture until it cools to room temperature. When cool, strain the water and use it to water your plants. The remaining eggshells can be added to your compost pile. Note: If you are not able to change the soil in your flower pot yet, making and using this eggshell/eggshell water can still benefit your plants.