I cleaned the case with a microfiber and "Simple Green" degreaser, which is my go-to for removing dirt and old wax and polish. And it was flat-out filthy.
Second step was to brush on a coat of garnet shellac. That looked great, but extremely shiny; the problem with that is the organ originally had a rubbed-out satin finish; mentioned explicitly in the catalog description. So I took a felt rubbing block saturated with mineral oil, and a bit of FF Pumice, and started rubbing with the grain, then used an old toothbrush to get in the moldings and crevices. Then I started waxing (used Dark Mahogany Briwax). When I ran into a spot that was still too shiny, I got a little wax on the cloth and touched the spot to some more pumice, and rubbed the wax/pumice in. I had to do this in a couple of spots. To get into tighter and more irregular areas, I did the same action with the toothbrush, generally working with the grain whenever possible.