Works pretty well. after a little trial and error, I put some DE earth on the floor (to keep the ants away from the bait), and I set the trap right on top of that DE powder, the trap was baited with some bread and peanut butter.  I set it on the floor of my tool shed, and it caught 3 mice that day, and I think that is all the mice there were, because the next day it didn't catch any.  I released the mice onto the grass outside, hoping that at least I would be giving a meal to one of the few stray cats that live around here.  That's not what happened.  What happened was a flock of nearby chickens saw me releasing mice on the grass so they immediately came running over and they killed the three mice in about 2 seconds, after that the chickens started playing a game of soccer with the dead mice, they were running after the the chicken with the dead mouse in its beak and everything.  That was quite unexpected, I didn't even know that chickens hunted mice.  So much for the humane way of setting them free.  Oh well, at least the mice did get a dignified funeral.