I only cook in cast iron. You want it to be properly seasoned with fat, so it gets that nice black coating on it. To do that, you coat it in oil and heat it in the oven. You can find more detailed instructions on google.
To clean cast iron, it depends on what was cooked. Generally if it's something fried in fat, I just heat the pan slightly, and wipe it clean with a paper towel. If it was something saucy and messy I run it under hot water, wipe it with a paper towel, heat it on the stove until it begins to smoke slightly and all the water evaporates, and re-coat with fat.