@MissCourt - How I prep it depends on if I'm going to paint it or not. I usually leave some of the grease on it if it's an outside piece of work or if I'm not painting it.
I use mineral oils to clean it. Just grab a box of wire scrub brushes and a pair of leather gloves. Scrub it with the mineral oils and then wash it off with really hot water. Pat it dry with a towel.
If I'm going to paint it, I just wash it like usual and then use regular old enamel spray paints.