If you own a system like the Dreamcast, SNES or NES, then you'll be aware of the fact that older consoles with white plastic shells begin to yellow over time. This is because fire-retardant chemicals are present in the plastic, and as these oxidise over time, the colour of the plastic changes.
For years, retro fans have been using a process known as "retrobrighting" to reverse this process – I've got an original 1987 PC Engine (which was a hideous yellow colour when I bought it) that was retrobrighted a while back and is now closer to its original white.
However, YouTuber Shelby Jueden – better known as Tech Tangents – has made the rather dramatic claim that retrobrighting actually causes more harm than good.
In a new video (thanks, Tom's Hardware), Jueden explains that he partially retrobrighted a Dreamcast back in 2015, but then left the disassembled console on a shelf for the past decade.
Upon returning to it recently, he was alarmed to discover that the retrobrighted portion of the console had actually become even more yellow than the untreated sections – and that the retrobrighting process had damaged the plastic, leaving streaks and blotches.
In conclusion, Jueden says he won't be using the retrobright method on his retro hardware again – and I'll be following his lead.