I have a model A and I want to paint the underside of the fenders and running boards. I want to use and flat black undercoat or gravel guard protection but nothing that will look ugly. The car does sit low but you can see under the front fenders. I would prefer to use something from a rattle can that I can get from an automotive paint supplier. Something with quality. Something that will stand up well but not to thick and blochy looking. I don't mind a semi rough finish. Any suggestions would be appreciated. Oh ya and would I use a solvent type cleaner to prep the area for dirt and whatever?