It is possible to draw directly with a Crayola washable crayon on a clean lightly sanded deoxidized plate. In order to get a drawing-like image you can draw on a heated hot plate with a crayon and it will melt. It will draw better than using it cold.
After your drawing has cooled take the new blue ground and roll ink over the plate covering the washable crayon. An even thin coat of ink works best. Heat the plate 350 degrees F/37 degrees C for 5 minutes to set the ground. Then wash off with warm water. The water will dissolve the washable crayon.
On aluminum it is not necessary to aquatint because of the coarseness of the metal. This mimics an aquatint. However when using copper you should apply an off set aquatint. Deoxidize the plate prior to etching then etch.
