Stain removal is all about speed and technique. Here's the proven method for tackling crayon from walls effectively.
Apply non-gel white toothpaste to a soft cloth. Rub in circular motions on the crayon mark.
Magic erasers are highly effective on crayon. Wet, wring out, and rub gently on the marks.
Make a paste of baking soda and water. Apply to crayon marks and scrub gently with a soft cloth.
Spray WD-40 on a cloth and rub the crayon. Wipe off any oily residue with soap and water afterward.
Once the crayon is removed, wash the wall with mild soap and water to remove any residue.