Due to the P.O.’s run-in with freshly-painted white paint, supposedly years ago, I redid the wheel wells with Napa #4501 Body Shield, rubber-based undercoating. The chassis grime is best removed by Simple Green and paper towels (no green pad or other harsh scrubber as to introduce scratches into the paint), followed by a “waxing” of Meguiar’s Cleaner Wax in the maroon jar. The cleaner wax removes the Simple Green residue and cleans the harsher areas where the Simple Green missed. It’s a great product and I learned of its cleaning ability while restoring Land Rovers. Once cleaned/waxed, the chassis is must easier to maintain, especially after mudding activity.
I’m not completely off my cleanliness rocker, here. I’ve always enjoyed routine maintenance more when I have a clean area to work with.