After disassembly, what's left is an empty frame. Unfortunately, all of the panels except for the main panel shown below (register displays and toggle switches) was wired into a single cable harness. To get the panels out, I had to cut the harness, but then, I was going to get rid of it anyway.
I cleaned all small detachable parts (knobs, button faces) by soaking them in mild laundry detergent overnight. Remember how much tape residue was on the buttons? After cleaning them, they're readable again.