A loyal reader has sent in a good tip: Rats are habitual creatures. If they come to think of rat traps as their friends, they are more likely to get caught in a trap. So, when you first bait the trap (peanut butter is the choice of most rat trappers, but NOT organic peanut butter which rats hate (not kidding)), do not spring loaded. Then, the rats will "learn" that the traps are friendly sources of food. Once you see that a trap is being treated as a food source, you can set the trap and it should do its trick.