I used fine-point Dremel grinding bits to remove most of the beard and followed up with extra-fine sandpaper and small hand files. It's not perfect; up close (which doesn't show well in the pic) he looks a little "scarred" around the mouth from the goatee removal (I'm working that into the character bio.) I covered up the worst of it with a light layer of paint that blended in surprisingly well.

I had originally planned to use a ST/VvV Grunt head, which I spent time hollowing out to fit--only to find out it's a hair too small! The result would have been a pin-headed Rock Steady.