Vine charcoal on paper. This was a broken wristwatch that I used to carry around.

Vine charcoal was fun to work with. It's very easy to smudge, but unlike a lot of drawing materials, it's actually possible to erase. I was even able to erase it with my breath. Whenever I drew part of the picture and it didn't look exactly right, I carefully blew away the problem area and redrew it.

Once you finish a charcoal drawing, you can spray it with a fixative to protect it from blowing away or smudging.