Freeze the crayon wax with some ice cubes. If the item is small, you can place it in your freezer for a short time. This will harden the crayon wax, and then much of it can be scraped off using a butter knife.
Place the stained area between a few layers of paper towels. Press on the area with a warm iron. This will slowly transfer the crayon wax into the paper towels. Replace the paper towels several times to keep the stain from spreading.
Apply a prewash stain remover to the area and let it sit until dry. Wash the fabric with color-safe bleach. Use the hot or warm water settings on your washing machine. Repeat as needed until the remainder of the crayon wax is removed.