First, collect data on current blurts per hours. Then, come up with a reasonable goal and reward. It will also help if you have a behavior replacement. I used Velcro on the back on the numbers. Whenever a student blurts, I will take the number off starting at 8. If they stay within the 1-8 number range, then they will receive a link on a paper chain. Once the chain touches the floor we're going to have a big shindig!