De-yellowing

[Tothwolf]

On Sat, 22 Aug 2015, Jules Richardson wrote:
> On 08/21/2015 05:28 PM, Evan Koblentz wrote:
>
>>> So, how does one de-yellow something?  I have a VT-100 and some other 
>>> gear that could use that process.
>> 
>> Google for "Retr0brite".
>
> I've never tried the stuff - but is it a permanent fix, or does the 
> yellowing gradually come back?

It almost always seems to comes back to some extent. De-yellowing 
treatments only work on the outermost surface of the plastic, and there 
are still plenty of free bromides just under the treated surface which 
will migrate outward. The re-yellowing (which may or may not be much less 
than the original yellowing) also occurs much faster than the original 
yellowing. Unless you can somehow eliminate all the free bromides from the 
plastic, de-yellowing treatments such as Retr0brite are just a temporary 
cosmetic fix.