Non-retr0bright de-yellowing.

[Wizard741]

Read this (here in Russian, but very useful article) -

https://ksportal.ru/901-kak-otbelit-pozheltevshij-plastik.html

[paul1981]

Yellowing is on top on a thin layer.
Also it comes back in a  2-3 months or a year.
I had a usb wifi card that turned yellow and used retrobright.
In 2 month period was like a canari again...
Even an A500 was back to yellow in a box.
Maybe just heat does the job.

So the best bet then is a can of white spray paint?

[paul1981]

Toothbrush + Toothpaste = White Color

How long does that last?

[Wizard741]

Hard to say. It all depends on the plastic and how to use it.

Use polishes. Such tools create an invisible film on the surface - it protects against external influence.
Read more: https://ksportal.ru/901-kak-otbelit-pozheltevshij-plastik.html

[vince_6]

Also some people use UV sprays, never tried them though.

[Wizard741]

This is also a good option!

[paul1981]

Hard to say. It all depends on the plastic and how to use it.

Use polishes. Such tools create an invisible film on the surface - it protects against external influence.
Read more: https://ksportal.ru/901-kak-otbelit-pozheltevshij-plastik.html

I'll get some Mr Sheen on my existing pastics then. As for old yellowed plastics I'm non the wiser!

[Wizard741]

Do as you see fit for yourself.
Before that advised - the truth.
Believe it!!!

When you clean the plastic or apply a layer of polish on it, it should be otdedelen from electronica.

[gertsy]

I know AMIGANs who have Retrobrighted and applied a clear matt spray paint and their kit has still yellowed. Results vary.

[klx300r]

I keep all my stuff in my mancave which is in a room in the basement of my house so no natural light to be found= problem solved for ever (or as long as my mancave stays put which God willing will be another 30+ years 

Be nice to hear from someone who used the clear spray and put the miggie back to exposed natural light to see if the yellowing came back

[paul1981]

These UV filter sprays and UV filter house window glass do they really stop plastics yellowing? Or is that you'd still have to keep them out of direct sunlight but that they help reduce the effect?
My first A1200 used to get morning sun for a few years, but even on the left hand side of the computer which was in the shade it still managed to yellow. So I think the sunlight (probably mostly invisible UV) must reflect off the walls and back onto the shaded area...yellowing it. This is where I feel the UV filtering may help.

Mancave? That's definitely the best bet. Of course, lock your Amiga(s) in the cellar and don't give them the light of day!