Several things I did to make it a "cleaner" event:
1. Made sure that I had washable tempera paints. (On sale for $0.99 for large bottles at Michael's)
2. Saved a Styrofoam egg container. I placed each color in am "egg cup" and filled the remaining "cups" with water for rinsing the brushes.
3. Supplied AJ with multiple brushes (he's not so great at rinsing yet).
4. And with rinsing in mind, I also gave him some extra paper towels to wipe off any excess.
5. I made a smock out of an old pillow case. I cut a circle out of the bottom seam for the head and two holes for the arms. This worked great!
Now that I know how easy it really was and how much AJ enjoyed it, I see more painting in our future.