Whiteboards are easy-to-use instruction boards that have taken over the roll of chalkboards in most classrooms. They are drawn and written on with dry-erase markers that wipe away with whiteboard erasers. Over time the debris from the erasers builds up to create smudges and smears that linger. Luckily, it's very easy to clean a dirty whiteboard without harsh chemicals.
Smear toothpaste over the affected areas of the whiteboard. The toothpaste contains mild abrasives that will effectively clean the board without the use of chemicals.
Wet some paper towels with water. Use the wet paper towels to scrub over the toothpaste, using firm pressure and circular motions. Keep rubbing until the smears and smudges disappear.
Wet some more paper towels and wipe away all the excess toothpaste, switching the dirty paper towels out for clean ones when necessary. Finish by rubbing a soft cloth over the damp board to dry and shine it.