I normally don't endorse brand names but I have to tell you that the best way to get rid of practically ANY mark on a wall is to use Mr Clean's Magic Eraser. I haven't found anything that is easier or better for taking off marks. I have used this product over and over in my cleaning and 99% of the time it can take off any kind of mark. They really got a good product in this!
Hope this helps! Have a good week.