I recently picked up a decent Tron CP from HooPZ, and was able to successfully remove the old overlay (and subsequent gooey adhesive) using a combination of Goof Off, a small wire brush (useful in the rounded corners), and a sanding block.
The lesson I learned in this exercise is to be patient with the Goof Off, and allow it to soak in for about 10 minutes or so before attempting to remove the "bottom" layer of overlay material. This allowed it to be peeled off fairly easily in sheets. Otherwise, attempting to remove it while still saturated with solvent resulted in it disintegrating in my hands.

Once all the gunk was removed, I then applied a layer of Brasso to give it a smooth finish, ready for the new overlay.

See the attached picture for the result.
galaga69