Since earthenware absorbs water, extra care is necessary before and after using it.
Before using:
Soak the earthenware in water for 30 minutes. This makes it less absorbent of water or oil.
After using:
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.