Actually I'm using a combo of shoulder- and elbow- grease. I thought of using a power tool, but didn't want to be cleaning the compound off of the ceilings, windows, cushions, etc etc ...

I used the stuff on the outside of my old Com-Pac, it worked pretty well there, too. However, the oxidation was much worse, so it didn't quite come back up to as good of a shine as you see in the cabin liner pics. I also used elbow grease on that, so maybe a power buffer would have been the better way to apply it for that job.