The oldest used coloring technique is charcoal. In earlier times burnt pieces of wood were used as charcoal; nowadays, a mixture of carbon powder and hazelnut is used. Charcoals are heavy in color but they blend more easily than pencils because they give off a fine powder. The only way to make corrections while using charcoal is with a cloth. The best way to blend charcoal is with a blender, piece of cotton, or a finger. After using charcoal use a glue spray to keep the charcoal in place.