I have been doing this for a while using a handmade chart for the whole class blurts. This year I decided to do individual blurts for students of course accompanied with many other positive reinforcements. The purpose of this chart is to bring awareness, not to punish. Reaching all the blurts on the charts can mean nothing other than a conversations such as , "oops, we had a lot of interruptions friend!, what can we do about this?" Rather than a blanket punishment.