Rub the markings with a regular pencil eraser. If that doesn’t work, try an art gum eraser. Wipe away any eraser leavings.
Dip a damp cloth in baking soda. Wipe the baking soda over the pencil markings to remove them. Rinse with clear water.
Place a dab of toothpaste on a damp cloth. Rub the toothpaste on the marks to remove them. Wipe the toothpaste off with a separate damp cloth.
Mix a drop of dishwasher detergent with some water to create a sudsy mix. Wipe the detergent mixture on the pencil markings. Rinse well.
Mix 1/4 cup white vinegar, 1/2 cup ammonia, 1/4 cup laundry soda and 1 gallon of warm water. Wipe this mixture onto the pencil markings. Rinse with clean water.