Baking is a lot faster and more convenient than this, and less messy. And with baking you don't lose the nice egg remnants on the shells, which are a bonus for the chickens, they don't need to be washed off.I've never baked the shells, not knowing that was the way to do it. I rinse them and then gently boil them for 3-5 minutes, drain, rinse again and let cool. They are perfectly clean and white and crush easily with your fingers.