Another warning.

[MeJasonT]

This is becoming a very informative and interesting thread.
Having turned my hand at anodising im well aware of the potency of the little 1ltr bottle of Caustic Soda. Its being used to clean the aluminium prior to being electrificated in sulphuric acid to open up the pours in the metal surface to allow the die to be absorbed.
The caustic is mixed to 1 tablespoon to 2 litres water and it really does get the metal clean, i've also used the same concentration for light rust removal and it has brought the metal up like new.

People have a tendency of worrying about acids but don't treat strong alkaline with the same respect, hence Tony's pot.

Fumes from such substances are also seriously hazardous to health and well being.

JTG will make it sound much more technical than I can - its great to find a Chemist amongst our members and going to be very useful.