[robespierre]

Those look like they could be cleaned up using a fiberglass pen (polishing to get to bright copper), activated rosin flux, and tinning with a cool-ish soldering iron (like 300° C) [lower temperatures keep the flux active longer before it burns up]. You might have to scrape the soldermask off with a scalpel to polish the whole copper pad. Also a cotton bud in 5% acetic acid followed by a water rinse can help with removing corrosive junk (although there are better solutions for ultrasonic cleaners).