Arrange clean, dry paper towels on a flat surface. Open the textbook to the page with the ink to be removed and place the textbook over the paper towels.
Dip a cotton swab in acetone. Acetone is the active ingredient in nail polish and paint removers. Pure acetone can be purchased at many drug stores and hardware stores.
Dab the ink mark that you want to remove with the cotton swab dipped in acetone. Discard the cotton swab after dabbing it on the ink mark once.
Repeat steps 2 and 3 until the ink has been removed from the textbook. Allow the textbook to dry and discard the cotton swabs and paper towels.