A great use for all of those eggshells that would otherwise just be thrown away:
Grind 6 dry eggshells in a bowl (mortar and pestal work great). Toss any large unpowderized pieces. Mix 1 TBSP eggshell mixture with 1 tsp flour, and 1 tsp hot water. Add a drop of food coloring if desired. Mix until a thick paste is formed. Roll into a chalk shape and wrap tightly in a paper towel. Allow to dry for 72 hours before removing from paper.
