I have been using lunch trays for kindergarten art for the past couple years now and they have transformed the fast and furious, once per week, thirty minute classes with my littlest students. The idea behind the lunch trays came from my work with choice-based art and the Montessori approach of spending extended time with an object, media, or idea.
Recently, my kindergarten students experimented with soft-lead pencils, colored conté crayons, mixed color shape crayons, and regular pencils. We looked around the room for lines, brainstormed different lines, and then they were set free for some time experimenting with the materials. I brought them back together after a period, and showed them a couple techniques with the materials. I demonstrated using the conté crayons on their sides, smudging the soft lead pencils with white conté crayons to make them look furry, and smudging pencils with your finger. See if you can find those techniques in the sampling below.
I love the freedom that this kind of choice gives my kindergarten students, but at the same time, it gives them some structure. They are still learning procedures and processes in the art room, and this gives them an easy way to clean up, but also maximize their short time in the art room.