How to make Eggshell Powder
Save up the cleaned and dried eggshells at room temperature, preserved in an air-tight container till you get up to twelve of them.
Preheat your oven to three hundred degrees Fahrenheit
Get a baking sheet and spread the eggshells evenly on top of it for about five to seven minutes. Baking them longer than this produces an unpleasant smell and damages the calcium.
At this stage, the egg shells should still be white with some brownish burns, now grind the eggshells using a blender for about a minute or until you get a fine powdery texture with no sharp edges.
The final product can be preserved at room temperature in an airtight container but not for more than two months.