Many crayon artists (you can find a few online) use solvents to soften their appearance. It can be a wonderful look but, personally, I love the pixilated look the crayon creates when applied just as is. Look at the art examples in this post _ you can see the speckled look crayon has when applied in layers. This adds to the realism, especially when creating an out_of_focus background, such as in these two images.
In fact, taking a crayon or colored pencil to paper is a therapy method that dates back to the early 20th century _ though it seems people are just starting to rediscover its benefits. So how exactly does something as simple and seemingly childlike as filling in the lines lend itself to combating adult amounts of stress?