I have had luck with Lestoil or GooGone to get a little bit of crayon out. One of those products will work to get the crayon off the inside of your dryer so it doesn't spread to your next load of laundry.
http://www.goodhousekeeping.com/home...s-crayon-may07
Here are some more ideas (towards the bottom the page I linked). Several sites recommend using WD-40 on a paper towel to wipe your dryer drum clean. Both Lestoil and GooGone are petroleum based cleaners, so I think that's why they worked for me to dissolve the crayon.