I got mine in my apartment complex...
Corpies can get upset unless you check with someone first - I'd try maintenance, not security or IS. Tell 'em you're a hobbyist, and want 'em for the parts.
Let's see - I've found PC's, Macs, monitors, keyboards and mice. At least here, they put the PCs alongside the dumpsters so true 'diving' is unnecessary.
Good luck!