I don't think the crayon smell is harmful in anyway. Though I'm no rocket scientist or anything...but there's nothing "wrong" with the car because it has that smell. My crayon smell has disappeared...and I didn't do anything
I actually kinda miss it.
I guess if you don't like the smell, get a "new car smell" air freshener. Those things are so strong...I doubt you'd smell anything BUT the "new car smell"
But again...why erase that lovely crayon smell...I wish I knew what caused it and could get it back.