[snotterite]

Air Body Saw with lots of wax on blade. Milwakee general purpose metal blade, go slow and use wax every 6 inches. Other blades cut faster but this combo gives you best control and clean edges.......Bolt Supply House has every thing you need
Or a plasma cutter if you can get the torch head in there.......If useing a plasma un hook batteries and electronic modules to be safe.
Be sure to use wheels made for alluminum.....ordinary ones will glaze ..... be hard to control...and increase heat...and cause destortion.