2. Egg skin can be used as fertilizer for flowers. Calcium carbonate contained in it is beneficial to plant growth, can promote flower growth and adjust soil pH value. When you use egg skin, you should dry it first. After drying in the sun, it can be used by mashing it, and it can be mixed into the soil by putting it in a pot. You can also soak in water for fermentation, and when the water changes color, you can dilute it with water to water the flowers. It should be noted that don't use it directly, it is easy to attract insects.