The problem arises when one then glues the joint together and the glue fixes the pencil mark in place.
Today I put a pencil in my drill so that the eraser end was sticking out and when about spin erasing the pencil marks. It worked. However what was needed was a special type of eraser; one that had a little more pencil on wood erasing power.
This item could be made and marketed to carpenters.
I would attempt to patent one myself but I do not have the money to do so. And the satanic race has monopolized the patent industry! So the best that I can do is state that I thought of it independent of anyone else and make the idea available to everyone. To the Satanic race those whom they make into schizophrenics are their Golden Gooses.