I've never tried a resist with oil pastels before, just crayons. I should give it a shot, these look great! (And I love Wayne Thiebaud!)
Actually oil pastels work even better, I think, unless you are looking for fine detail. Sometimes it's hard to get kids to press hard enough with crayons, but it's rarely a problem with oil pastels. Glad you like these!
My third graders just finished Wayne Thiebaud projects, but we created batiks using tempera paint (a technique I learned from Art is Messy). I love introducing his work to students, and they are always happy to create the most elaborately decorated cakes!http://artabroad.blogspot.com/2011/06/beautiful-batiks.html