Before initial use, add a small amount of water to the pan and heat on the stove to remove the protective coating and any stickers, dumping the water and repeating several times. Next, wash the pan with hot soapy water. Dry thoroughly.
Traditional steel pans will change color after use. To reduce rust, clean with hot soapy water, hand dry and coat the interior of the pan with vegetable oil. If rust does occur, clean with steel wool, then wash and coat with oil.
A paella pan can warp if left on a burner too long without anything in it.
Stainless steel and non-stick pans do not require the above care. Avoid abrasive cooking or cleaning tools with stainless steel and non-stick pans.