Pencil Rubber

For one of my classes I do a pencil that can write and erase on paper, but I am not allowed to use anything for a real pen (rubber wood and graphite).
So I thought today that I could use charcoal or possbley somthing like that?
So if you have any ideas can you please tell me? Thank you.
Ps THIS IS NOT A RIDDLE on posting REAL!

Oh, great. Cheating on an assignment to think. What did you think. They teach lol thought so little at school, we can hardly miss class. Oh well, at least we can learn networking in this way. Maybe.

Yes, charcol would bee good. would be slate. that ERAC better.

Your idea of charcoal would work.

Perhaps the use of charcoal and clay. If you do not find a good way to incorporate the clay into the charcoal for your pencil, you can use clay at least as gum. Check out these links.
http://en.wikipedia.org/wiki/Pencil
http://en.wikipedia.org/wiki/Charcoal
http://en.wikipedia.org/wiki/Eraser

Take a stick.

Burn.

Carefully, gently, and draw on paper.

Eliminate dust.

Delete as appropriate.