Oh, and did I mention that it's made out of almost entirely upcycled materials? Two Altoid (or similar) tins and scraps from an old sweater make up the base structure and the eraser pad. A little glue to hold things together, paint to make it look pretty, and voilà! I used orange spray paint that I had leftover from a previous project and a simple hand-lettered title for my design, but (naturally) you can make yours with whatever design you like.
Step 1: Materials
2 Altoid tins
part of an old sweater (you'll need about 4X10" rectangle)
2 part epoxy or another glue suitable for gluing metal to metal and fiber to metal.
a few inches of wire or twine
Steel wool, or a wire brush
needle & thread
You could really make any size/shape of eraser using this scheme, but an Altoid tin fits spare chalk perfectly. Whatever shape you choose, you'll need to get two tins that are exactly the same size. An old felted sweater (or other knitwear) makes a perfect eraser pad. The type of fiber doesn't matter too much, anything thick and knit will do the trick.