Then I found Victor (same company as makes the regular snap traps) Easy Set traps. They're pre-baited with pheromones or something and the second the mice touch the trap, whammo. Some reviewers say they're hard to set without triggering them but I didn't have that problem at all and wiped out an infestation in just a couple of nights after maybe a month of trying with the regular traps. Maintenance came to spackle up the hole behind the oven that they were coming in by but by then it was over. If you ever have mice again I highly recommend them.
I actually have a pack I haven't opened yet. I've just heard and seen mice, but they haven't gotten into the ramen or dog food yet so I'm not pissed enough to kill them.