To reuse eggshells safely, the most important step is cleaning and sanitizing them first. Start by rinsing the shells to remove any remaining egg white, then place them in a pot of water and bring it to a gentle boil for about ten to fifteen minutes. Once boiled, drain the water and let the shells dry completely on a clean towel or baking sheet. After they’re fully dry, store them in a sealed container until you’re ready to use them. This process helps keep things hygienic and makes the shells easier to crush or grind later.