system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: Why does some materials turn yellow-ish instead of white when exposed to sunlight (or UV) for extended period of time? Why that color specifically?
gpt
As regards ABS plastic specifically (the kind used in game consoles like the Super Nintendo as well as some older computers), this yellowing occurs because when it was being put together, the manufacturer added a special chemical to it to act as a flame retardant.

This chemical has the element *bromine* in it, and over time, sunlight can tear the bromine away from the chemical. The bromine then combines with oxygen and becomes yellow.