Love the close up photos. Corrosion is not always what can be seen. A lot of the times, corrosion has traveled along sections of traces that look fine until you sand away the surface. The "through holes" are also notorious for hiding corrosion. As a hobbyist, I enjoyed repairing these boards. As a business, it is not worth it. But "when" I have the time, I do like working on the really bad ones.