1. When cooking eggs, adding a little edible vinegar can promote the anticoagulant effect of the protein, so that the eggshell will not crack easily.

2. When eggs are boiled in cold water, the temperature of the eggs will gradually increase with the water, which can avoid the situation that the eggs are cracked when they are boiled in hot water.

3. If the raw egg you want to cook has cracks, you can add some salt to the water. In this way, the salt water can accelerate the protein coagulation at the crack and prevent the protein from overflowing to a certain extent.