There's something about red crayons - they just won't come off the wall no matter what I try.  We try to control the crayons whenever the kids are using them, but somehow they walk off anyway.  The kids break them so there are twice as many to try and contain, and they skillfully hide them I think for use when we're not looking.  They recently started a mural on the wall in the living room behind the couch where we didn't even find it for a couple of days, and one day the boys snuck some crayons in for nap time and the whole room got a makeover.  Some of the things I tried to remove the art from the walls with didn't work at all (window cleaner), but others worked on most of the marks (Mr. Clean Magic Eraser got most of it), but NOTHING worked on the red at all.

Today my husband says "you know, I heard that furniture polish might work."  So he goes and gets some out of the cabinet (ours was Scott's Liquid Gold Wood Cleaner) and with just a bit sprayed on a paper towel he proceeded to get all the red crayon off the wall.  It was amazing, didn't even take much effort.  We were worried about discoloration so I'd recommend trying a small spot first but honestly there was not much chance of the walls looking worse than they already did   I just wish I understood how he could go through weeks of listening to me gripe about the walls before coming out with this gem of an idea.