I would tell them, what would happen if they do like this.
I would try to advice them, if they didn't obey I would take it to the class leader.
I would ask them, "Would u break the furniture in ur home?? Then, y u are breaking it in the classroom."
As everyone knows, Soft tone will even change the minds of hard people.
Even after if they didn't obeys, there is no way other than informing to the teacher.