Production of hydrogen through the reaction of aluminium metal and sodium hydroxide If I have a solution of 25% $\ce{NaOH}$, and I simply add a cut-up aluminium can or some aluminium foil, will it react into hydrogen and sodium aluminate? 

In principle this reaction should happen, but it didn't work when I attempted it. Perhaps an oxide layer prevented it, or a protective layer of sodium aluminate was formed. (Perhaps my experiment was faulty.) Should this happen, and what can I do to fix it? (My goal is to generate hydrogen gas.)
Oxide layer would not hold against the strong alkali, and sodium aluminate does not form protective layer either. I suppose cans and foil may be covered by some coating, to make them suitable for food grade applications. Try burning it off, or rather use other sorts of aluminium (cut-up wire, maybe). Normally it would react quite vigorously.