Brown paper grocery bags, packing paper, paper towels, cardboard egg cartons, junk mail, pieces of a cardboard box, or strips of a charcoal bag will all do the trick. Really, all you need is a ...

Use an eraser to rub away the charcoal to create highlights. Combine with chalk to add highlights on a mid-tone paper. Brush over with water to deepen the tones and fix the charcoal.