Good day everyone, I am plan on writing in course books to help studying. I am almost certainly sure this will help me understand the material better. The question is if anyone has experience with writing in books and is there a huge difference between using a pencil or using a light-coloured (e.g. yellow) pen? The advantage of a pencil is that you can rub it off but often leaves marks, the advantage of a light-coloured pen is that it will not distract as much. Thanks in advance.