(Top: That's what Mika's masterpiece resembles and the lines are about 3 ft high and covers the length of my wall about 6 ft wide)
Last night I received a message from a friend who so happened to read my blog. Apparently she too had the same problem with pencil marks on the wall. However, her problem was solved with a little Axion and a rag. Happy, I got out my Axion and rag only to realise that the pencil marks weren't coming off because they weren't pencil marks but PEN MARKS! Oh how short-sighted could I be? I definitely have to get a new can of paint now and repaint that wall. Argh! No wonder the kids couldn't erase the lines at all.
I did a yahoo search and this is what I got:
Q. How can I get ballpoint pen marks off a painted wall? REBECCA LEONG, Newton A. Rubbing alcohol is the cleaner most used for such marks. Others are acetone, Stain-X Carpet stain remover, sold in grocery stores; Ink-No-Mor, toothpaste, Vaseline and dry Brillo pads. With all these cleaners, try them on an obscure area to make sure they don't stain, rub off or affect the paint in any way.
I went to other sites but alas, no luck.