As a practicing student in the art of aluminum work, there are several cautions that must be considered. Aluminum is a soft material, and often is claded, which is a sandwiching of pure aluminim sheet over the alloy sheet, providing corrosion protection. Blasting away with sand, silica, glass, plastic beading may remove the cladding material that is used on our machines. I've removed lots of paint off of aircraft skins with a fine grade of walnut media, and a low air pressure blasting pot. The walnut media is completely bio degradable, and most times wont even pull off the alodine chemical coating that is applied prior to priming most paints. It will leave a soft matte finish if the pressure is too high, and too high starts at 60 or 70 psi. Typical blasting pressures start at 100. I haven't tried baking soda or cornstarch blasting, but the airlines are using both with decent results.
Chemical strippers: I stay away from them like the plague. The chem strip is a great product, used for many many years, but is being completely replaced by media blasting and strobe "flash" paint removal techniques... now there's a cool Buck Rogers trick. High energy strobe pulses of light beating the paint away. The chemstrip works its way into the seams, and will eventually begin corroding the metal, and obliterating the sealing tape that is used at the seams.
So much more to cover on the subject, but that's an overview. Let me know how things go~