Hi Jaqueline. I have a suggestion you can try, but please pick your least favorite item and and/or an inconspicuous spot. In the past we've had a lot of success with WD-40 in getting out crayon from other items. I will admit I've never tried it on clothes. It is oil based, so it will break up the waxy crayon, but it will also leave an oily residue. You will need to rewash the stuff after you use it in hot water and detergent. It will take detergent to break up the oil.
We have used WD-40 to remove crayon, grafiti, and sometimes even permanent marker from chalkboards and other surfaces with great success. You always have to follow it with some form of detergent. On the chalkboards we used Joy dish detergent after it.
Also, it might be worth checking out www.ifi.org. That is the International Fabricare Institute, a professional drycleaners organization.
Good luck.
~E.