Soak the casserole in salt water for 72 hours. Soak the casserole in salt water to ensure that the casserole is full of water. The salt particles in the salt water can fill the small gap in the casserole, so as to prevent the casserole from cracking and make it more durable.
Don't use the casserole when you first buy it. First pour an appropriate amount of salt into the casserole, then fill it with water, stir it in the casserole to fully dilute the water and salt, then cover it and soak it for 72 hours.
Generally, in the process of making casseroles, there will be many small gaps. If the newly bought casseroles do not deal with these small gaps in time, they will be easy to crack when using casseroles in the later stage.
The function of the casserole soaked in salt water is to make the small gap in the casserole filled with small salt particles, so the casserole soaked in salt water is more durable and prevents cracking.