So this is sort of the current state of that previous corrosion. Let me see if I can do a before-after.

I was also unaware of the need to desocket chips before washing... live and learn... And either I or more likely someone else and possibly also I have corrosion issues with the Video ROM (UK6). I hadn't realized that when the board powered up (which it does) something should have been happening with the (green) screen.