Scrape off excess crayon gently with a plastic scraper or old credit card
Rub the mark with a dry microfiber cloth
Apply a small amount of baking soda and water to a damp cloth and gently rub
Use a magic eraser lightly on painted walls
Wipe with warm water and a few drops of dish soap
Try white vinegar on a cloth for stubborn marks
Use toothpaste without gel on a soft cloth and rub gently
Apply a little WD-40 or cooking oil to a cloth, then clean with soap and water afterward
Test any cleaner on a hidden spot first
Dry the wall with a clean cloth after cleaning