My Amiga 500+ was looking like new when I got it. I used it occasionally but then it was stored for years boxed up under my bed. There's also a radiator right next to the long side of the bed. When I pulled the amiga out of storage for inspection and some games, it turned out that it has yellowed! I guess heat from the radiator helped speed up the process.
Anyway, just another first hand proof that even things kept in the dark can go yellow
Anyway, just another first hand proof that even things kept in the dark can go yellow