Well, you could sand away pencil marks, and hope you don’t gouge the wood or go through the thin veneer of expensive plywood. But, there is a better way! – Alcohol! No, not that kind – this kind – denatured alcohol.
Building cabinets, I try to minimize layout marks since the surface will be either clear-coated or stained, and marks can easily show through. Nonetheless, some marks are needed, such as these to layout a course of shelf pins.
Soak a small rag in the denatured alcohol, and give the marks a good rub until they fade and disappear. It doesn’t take too much.
Allow the alcohol to dry
Take a good look – marks are gone! There may still be some faint marks left, but they can easily be lightly hand sanded and they will be history. The denatured alcohol method works well also to remove most yard markings and small smudges from the surface of the wood, or fade them well enough to facilitate a light sanding.
Credit to Wood Magazine