Stripping stuff with Caustic Soda

I've heard a good old can of coke eats away aluminium oxidation. I'm sharing a can with the frame now.... i'm not actually sure if I want it to work! But i do wanta try and keep the stem and seatpost, they're probably worth more than the frame.

Coke does this because of the phosphoric acid in it. You can buy much stronger phosphoric acid as a limescale or rust remover from hardware shops under the brand 'Hagesan Blue'.