You could re-tin the contacts with fresh solder and then use solder braid to make the contacts flat again. That should improve the contact reliability.
The nice thing with tin plated SIMM contacts 😀

Otherwise you could probably clean it back a bit more, I use a ceramic tool to scrape off corrosion like that. You don't need to worry until you see copper, at which point stop. Then you might need to re-tin the pad.

Thermalwrong wrote on Yesterday, 13:38:

You could re-tin the contacts with fresh solder and then use solder braid to make the contacts flat again. That should improve the contact reliability...

Thanks Thermalwrong. I may try re-tinning at some later date, but right now I have too much going on to spend time developing a new skill.

I brushed them a bit more and cleaned the socket before shoving them back in. System ran the Compaq memory torture test for 1.5 hours with no errors, so I guess everything must be connecting ok for now.

Just curious - do you know why they made them that way? Copper connectors seem to not be susceptible to the same kind of corrosion, but maybe they cost more to make?

Copper oxidize faster when in open air. Back in the days when I etched PCB I would always tin the traces myself.
Then, one would argue that silver is a better conductor than copper, but also bad at surviving oxides. But you know, makers don't create things to last 30+ years: the market is meant to make you consume and replace superseded or broken objects. My 2 cents is they simply got engineered for the moment.