Dead set of carts!|Technical Corner|Forum|SNES HUB

A buddy of mine gave me a SNES which was said not to work. The SNES works fine, but every single cart he had is dead. I’ve never seen anything like it! I thought these things would still be around for the cockroaches to play after nuclear war. Any idea what could have caused such a thing on over 10 carts? I haven’t torn into the carts yet because I’m waiting for the correct tool in the mail. (I’ve never had to get into one before.)