Here's a clayboard/scratchboard of Jamy la patate I did not so long ago. It was my first time with clayboard, so I'm pretty happy about it.

The reference picture was taken from metallica's website in the extras section.

Hope you like it :)

Here's a little description of the medium:

Clayboard is very similar to drawing with a white pencil on black paper, the basics are the same, but instead of drawing, you scratch the black to reveal the white under with a variety of tools. The boards are just a thin coat of black ink on a white background and you can get different kind of shadings depending on the pressure you put and the different tools (For example, I like using a little metal hair ball for shading). When you make a mistake you can put some India ink on the surface, but it will show up a little bit, so you better be careful :) I got lucky and didn't make a mistake on mine :) I used ampersand claybord tool kit. You should definitely try it, it's a lot of fun :) and the more contrasted your subject is, the easier it is! Try it out, it's a lot of fun!