Are your children budding artists?
If your children have decided to use the bedroom walls to create their latest crayon masterpieces, you’ll get excellent results by dipping a damp rag into baking soda and then using that mixture to scrub it off. Its the home remedy that my Grandma used.
Although a quicker way is to use a Magic Eraser, which, as a professional cleaner for the past 20 years, in my opinion is one the best cleaning products I have seen for quick cleanups. WD-40 does work very well at removing crayon marks, however you have to clean off the oily residue after with soapy water.