Crayon on Walls or Washable Wallpaper: Spray with WD-40®, then gently wipe, using a paper towel or clean cloth. If the mark is stubborn, sprinkle a little baking soda on a damp sponge and gently rub in a circular motion. If the WD-40® leaves a residue, gently wipe off with a sponge soaked in soapy water; rinse clean; blot dry. Another method is to use a hair dryer - it heats the wax and wipes away instantly. If the color remains, like red usually does, wet a cloth with bleach and wipe.
(Try with care!!)
(Try with care!!)