Yes, they are messy to work with and all kinds of fun when you add static to the mix...the particles either stuck to everything or went flying off in all directions.
Here is some progress with the paperclay I made last night. It is not going to be an actual skull per se, but I still need to shave down the brow ridges, mess with the cheeks and add some mass to the top of the head, but the first one—which I'll consider a test—is coming along.