You're not supposed to use soap, but some will argue that detergents are so weak today that it doesn't matter.
Water is okay, use a scoring pad (not one with soap). For light duty cleaning, I just wipe out with a paper towel. If there is light gunk stuck to pan, shake some salt in the pan, then scrub with a towel and oil. Then just wipe the salt and crud out and you are done. The salt acts as the scour pad.

Olive oil stays to burn at around 200 degrees, so while it's more healthy, it burns off before it can really help season your pan.