[GreenKeys] 33 cover cleaning

[John Nagle]

> Date: Sat, 01 Dec 2012 16:01:08 +0000
> From: Sam Hallas <s.hallas at ntlworld.com>
> To: greenkeys at mailman.qth.net
> Subject: Re: [GreenKeys] 33 cover cleaning
> Jim Haynes wrote:
>> A few years back on the telephone collectors list there was a lot of talk
>> about Retrobright for reversing yellowing.
> 
> You can read all about my experiments with Retr0bright at
> 
> <http://www.samhallas.co.uk/collection/retr0bright.htm>
> 
> I found that I could get the required effect by dunking the whole case 
> in a tub of TAED solution and left it out in the sunshine.


Search Google for "yellowed plastic".  The chemistry that causes
yellowing is well understood - it's from bromine used as a flame
retardant. The yellowing can be reversed chemically.  There are
various approaches, all somewhat messy.

				John Nagle