Ours didn't looks quite so powdery. I'm thinking I may have needed a little more baking soda and not so much shaving cream. It didn't matter to the kids they had a blast. I only had one student who would not touch the snow until I said they could write or draw in it. She then proceeded to write her sight words using just one finger. Not knowing how much each box and can combined would make, I only used 4 containers to mix in and one box of baking soda for each container. I added the shaving cream until I thought there was enough. I had 5 kids at each table sharing a tub.
Clean up was easy. I gave everyone a paper towel to start wiping off their arms. Luckily I am next to a small empty work room with a sink that has warm water. My assistant took the kids in to help wash off their arms and hands. When they were clean, I gave them each a baby wipe to get off anything we might have missed. I went around and wiped it out of their hair and off their faces. We rolled up the blue paper I had used to cover the tables with and swept up the floor. As the mixture dried it turned powdery and was easy to sweep up. Our custodian ran a dust mop through after school and all was good.
Next time I will
1. Do it outside
2. Use 8 tubs instead of 4
3. Give better directions on how to play with it.
What I learned from this experience is that my kids NEED more of this type of play. They need more sensory activities. I think they went wild because they have never had the opportunity to do anything like this.