Buy Washable Crayons!

Okay, first, the setup...my son has a little "colouring area" in his room, with a little table and chairs, and this is where we keep all the colouring books and crayons.

Soooo, about a week ago, he's back there colouring away. I'm doing my own thing until he starts yelling "Mommy! Mommy" I rush back to his room to check on him, and there he is, standing on the table, colouring on the walls. He wanted to show me his masterpiece. So I scold him. I'm thinking, it's no biggie, he's coloured the walls before and it comes right off. Wrong. He did his mural with the only non-washable crayons that we have that came as a party favour. I've been scrubbing for the last 4 days. I've tried nearly everything that's been suggested. I've tried plain water -- no action at all, Pine Sol -- nothing, baby wipes -- smeared the colour around, and dishwasher detergent -- best luck so far, but still there. The one thing that I've had suggested that I haven't tried yet is WD40, since that's not something I keep in stock. Gonna go get some and hope that works. Otherwise, I guess I'm going to be repainting.