Sharpie is a brand of permanent markers that are available in a number of colors and tip sizes. If you have written on a binder cover with a Sharpie, you may think that it must be thrown away when you want a clean one. Fortunately, the term "permanent marker" is somewhat misleading when dealing with smooth, plastic surfaces. It can be removed with a solvent such as alcohol, acetone or nail polish remover.
Soak a cotton ball with rubbing alcohol. The stronger the alcohol, the easier the Sharpie will come off.
Rub the soaked cotton ball vigorously on the Sharpie marks that you want to remove.
Repeat the process with a fresh cotton ball if the current one becomes saturated with ink.
Switch to acetone or nail polish remover if the alcohol does not remove all of the Sharpie.