[sdiy] Panel Finish

[Scott]

Anyone know what computer cases are made out of (or coated with)?  It's steel (magnet sticks to it), the outside is powder coated, but the inside is just shiny bare metal.  I've got stacks of cases that are quite old, sitting in a relatively humid basement, and none are rusting.  
I used one for a panel once.  Not even thinking, just cut it and drilled it like it was aluminum.. It was a little tough, but I didn't think much of it.  Then weeks later I realized/remembered it was steel.