Hi Doc, I was wondering if I could peel potatoes with sandpaper and is it safe?

This really won't work. Grinding sand or grit into the potato to get rid of the skin is sure to end up with a potato that has many foreign particles in it. Steaming the skin off or boiling and peeling by hand works much better.

Check out this innovative way to peel potatoes by Dawn Wells, Mary Ann of Gilligan's Island fame: Dawn Wells Potato Peeling Video