J.A.
Hi A.,
Luckily today's crayons are very washable. I would simply toss it in the wash with detergent and cold water. Do not use a pretreat such as Shout it has enzymes which are intended for organic stains not inorganic. If the crayon does not come out on the first wash, do NOT dry the clothes simply wash again. Good Luck.
J. L.