The use of highlighters certainly makes studying and marking notes easier. Sometimes, it makes it a little too easy to get carried away and highlight far more than was necessary or was intended. Then, it seems as if the marks are permanent. However, there are products that can help undo excessive highlighting.

Use an erasable highlighter pen to mark your books and notes. Then using an ordinary eraser, you can remove any unwanted highlighter marks.

Use the triangle highlighter (see link below) which comes with two tips for highlighting and one eraser tip.

Use a highlighter eraser pen. Simply mark the pen over the highlighter mark and watch the highlighter go away.