Date   : Fri, 09 Dec 2011 09:48:06 -0000
From   : helenandjohn.simpson@... (Helen and John Simpson)
Subject: Beeb Cleaner ?

I have used Retrobright very successfully myself on the following:

- Electron
- BBC B
- A3000

It's very easy to make up and I was able to source all the ingredients
locally in Derby. I just bought normal strength peroxide from the chemists.
Xanthan Gum was a bit harder to source if I remember correctly, I think I
got it from one of those health food shops.

My method was as follows:

1) Wait for a really sunny summer's day when you have about 3 hours spare
(this is by far the most difficult step)
2) Make up just a little bit in a jam jar - eg about 50-100 ml. It froths up
slowly so you end up with more than you expect.
3) Put the computer outdoors and paint the side facing the sun (using a
paintbrush)
4) Leave it for about 15 mins. Any longer and the retrobright just dries out
(and I think it doesn't work when dry).
5) Wash or wipe off, check the degree of yellowing, reapply.
6) Keep going until you have reached the desired colour. I don't think it is
possible to go "too far", because it only removes the bromine staining and
does not bleach the actual plastic colour.

The process is very gradual and controllable, it doesn't melt the plastic or
affect it in any way other than to gently remove the yellowing. Doesn't
affect key labels. Obviously it would affect paper stickers. I wore rubber
gloves at first but to be honest the stuff does not seem to be all that
dangerous - I got plenty on my fingers subsequently with no harm done.
Obviously I washed it off pretty quickly.

I did the first machine about 2 years ago and there is no sign of any
reversion to the yellow colour, or of any other changes to the plastic.

I hope this reassures people's understandable concerns. I'm not connected
with the Retrobright inventor(s) in any way, I just found that it worked for
me.

John