Thank you. Although I know it's possible, I decided it was too much for me to split the hem flanges on that panel and peel off the skin, deal with the rust, then later rebuild the whole hem flange all the way around, so I took n2omstr advice and dumped nearly a quart of Rust Bullet into it, sloshed it around to get into the corners, and let it drain. The exterior rear/bottom also had about 2.5 to 3" cut off/ replaced/metal finished and prepped so I wanted to protect that effort.
