Actually the correct chemical compound is sodium hydroxide. This compound is very usefull when cleaning aluminum but should not be done near an open flame or in an unventilated area. If the aluminum is cleaned using sodium hydroxide (a caustic) it must be nuetralized using an acid rinse (one particular acid works best).
Aluminum placed in a mixture of sodium hydroxide and something else (what, I am not telling) will liberate hydrogen gas. This gas can be captured but I am not recommending this.
I am not giving the percentages of what to mix with what as this can be a dangerous process and should only be undertaken by persons with the proper training and experience.
I will however say this, yes, the hydrogen gas that is liberated is flammable so please do not fool around with it. It can, will and has killed people in the past.