Does anyone have suggestions for getting marker off painted walls?

My three-year-old decided to decorate our plain white walls in the living room yesterday. We now have his beautiful artwork in black permanent (laundry) marker all over two walls. We have taken pictures to keep the memory, but need to get it off the walls. If I remember correctly, the paint is a semi-gloss.

So far I have tried the Mr. Clean Magic Erasers. It is working, but very slowly and stripping the paint with it. We are already planning to repaint the wall (they are still white from when we moved in), but we’d like to get the marker off as much as possible before we paint.

Does anyone have a better idea or suggestion for getting the marker off the walls?