Since earthenware absorbs water, extra care is necessary before and after using it.
Soak the earthenware in water for 30 minutes. This makes it less absorbent of water or oil.
Clean the earthenware as soon as possible, and dry it thoroughly before putting it in a cupboard.
Since porcelains do not absorb water and are relatively shock-resistant, you don’t need to take extra care. However, do not heat porcelains with painted decorations, or with gold/silver decorations in either a microwave oven or a gas oven.