In our experience what happens when you wash a board with alcohol is that it partly dissolves the remaining solder flux, and spreads it around in a thin, sticky, sometimes white and flaky, but all-around awful layer that remains when the alcohol evaporates. If you didn’t leave it soaking for a long time, my best guess would be that the finish isn’t actually damaged, so much as covered under a thin layer of thinned solder flux, which can be removed with great patience or a professional-grade flux remover.
Unless you’re using flux that *requires* removal or you are willing to pick up some solder flux, your best bet is probably to just hide the backside, and hope that no one asks to see– it shouldn’t be harmful.
And on that bug: Yep, you’re totally right. That jumper used to be called JP1. Somehow, you’re the first person to notice this after a couple of years, and a surprisingly large number of Peggy 2 kits out there!
