I decided to clean under the front spare tire and gas tank area.  It wasn’t as filthy as the rear luggage shelf area, but it certainly needed to be done.  You’ll see there was a good amount of surface rust too.  Here are some pics from the process:

Here are the “Before” images…

Cleaning With The MasterCoat Metal Prep (while wet).  You can really see the surface rust when it’s wet:

Here are the “After” pictures (much better)…