Eggshells are naturally fragile, which leaves them prone to cracking or completely breaking if they are handled in a rough manner. Hardening the shell gives the eggshell an extra measure of protection. While this will not prevent an eggshell from breaking due to a fall or extraordinarily rough handling, the eggshell will not be as prone to breaking when handled in a normal manner.
Things You'll Need
Clear nail polish
Apply clear nail polish onto one half of a clean eggshell. Sit the egg painted-side up in between two wadded-up pieces of tissue to prevent the egg from rolling over onto the painted side.
Allow the clear nail polish to dry for 15 to 20 minutes. Use a small fan set on its lowest setting to speed up the drying process.
Turn the egg over on its unpainted side. Apply the clear nail polish to the other half of the eggshell. Allow that side to dry for 15 to 20 minutes.
Remove the contents of the egg before hardening the shell.