When you get a reward for doing something with your mobble, don't click just one time on the button (diamonds or hearts), but click very fast more times. You'll have the chance of getting multiple rewards. This cheat work better if you try to slow down the speed of the smartphone, such as returning to the homescreen when the mobbles' app open the reward's prompt, open an other application an then return to mobbles' one (touch fast the bottons!)