Sandpaper or sanding boards are a pretty traditional means for shaping and sharpening graphite and charcoal. The main issue I have with sanding is that as soon as the sandpaper gets loaded with graphite or charcoal, it becomes sort of a “disease vector” that spreads dust around your work space if you are not careful. I recommend an alternative that 1) is less expensive, 2) makes managing dust much easier. I use a mill file. Specifically a 6 inch, “single cut, bastard” (yes, bastard…I’ll explain), mill file. It’s a flat metal working file. “Single cut” refers to how the file teeth are formed—in this case they run straight across the width of the file all parallel to each other—no crisscrossing. “Bastard” refers to the coarseness of the file. Mill files come in four grades of coarseness: “Coarse”, “Bastard”, “Second cut”, and “Fine”. (Nobody really knows why “bastard” became a term for coarseness.) These are relative to the length of the file: a larger file of the same grade has larger teeth. So…a 6 inch, single cut, bastard mill file turns out to have the best coarseness for replacing your sanding board. Hold the file stationary like you would a sanding block. Then you can run the pencil tip sideways along the file, rotating the pencil as you do so. Just make sure the angle is such that you don’t push the point of the pencil into the file teeth or it will catch and break off. Pull the point across the file teeth. Let the file do the work, meaning you don’t have to press hard—gently does it. To clean away the dust, use a tooth brush. Do this over your trash can and don’t brush so vigorously you create a cloud of dust! Brush along the teeth of the file (not across them), and the brush will remove nearly every bit of dust from the file. No dust “disease vector”! You can find these for about $8 at your local hardware store, which is cheaper than a package of sandpaper and it will last a lifetime (several lifetimes).