It is fun to work with sculpy but the chemical make up of the clay is dangerous for children. You need to get them to was their hands thoroughly after touching the soft clay. Also the surfaces which the clay it molded on (tables, etc) need to be cleaned well after. I use aluminum foil and tape it onto the surface I will be using that way I just have to fold up the foil and use it another day.
Warning #2 - the fumes from the cooking sculpy are rather stinky. The directions say something about a well ventilated area. That implies to me bad stuff in the fumes.
I only play with sculpy in the warm weather days when I can open my door and get fresh air into my house.