In article ,
Stuart wrote:

On Fri, 30 Sep 2005 16:23:27 +0100, Tony Williams
wrote:
....... or buy a couple of pounds of Rhubarb and
boil it up.

And don't forget the custard ..Yummy....lol

Sorry for the delayed reply.....

We used to use Oxalic acid to whiten-up aluminium
panels (I think it removes the copper, or something).
DIY'd from rhubarb, then bought as pure Oxalic acid.

The rhubarb juice produced a more pleasing 'whiten',
(less harsh), and was far easier to wash off.

--
Tony Williams.