The leather was fine. The part between the rubber sole and the leather shoe (I think it is called midsole?) just disintegrated.
The were stored in my shoe rack. I wouldn’t say that it is particularly humid there but it would be warm-ish (depending on the weather).
I wasn’t particularly shocked by this since they were simply lying around for that long. Maybe active use would have extended their life a bit more.
But maybe I can give them to someone that can add a new midsole so that they can be used again.
TranscendentalEmpire@lemmy.today 1 month ago
Most likely they were stored in a warm and humid place. Polyurethane foam can get something called hydrolysis, where moisture breaks down the polymers in the foam.