Step 1

Collect washed eggshells in the refrigeratoruntil you have a dozen or enough to fill a cookie sheet.

Step 2

Eggshells will begin to dry while in the refrigerator.

Step 3

Preheat oven to 200 degrees Fahrenheit.

Step 4

Spread the eggshells on a cookie sheet and bake10-15 minutes.

Step 5

If you washed the eggshells shortly before baking, allow extra baking time. Eggshells must be completely dry before grinding.

Step 6

Grind the eggshells in a clean coffee grinder or a blender until all large pieces are ground to a powder. A mortar and pestle is also a great way to grind to a powder.

Step 7

Store in a lidded jar.