Before putting the front panel label on the Vong-Filterung that you kindly sent me (I did think I had it working at one stage), I put a polishing wheel into the pillar drill and tried that. It wasn't a success.
I now have a USB -> MIDI box and will shortly have a Zoom patch switcher box which I want to polish up, both in 1590A boxes, so more experimentation is required. Polishing kit (three buffing wheels, three polished) now ordered from Ebay.