To eliminate the ones that are there, plain old fashion traps. I took care of three in the garage the past two days.
The old style traps work fine if you use needle nose pliers to bend the trigger catch a little to create a hair trigger. Harder to set but very effective. For bait I use Jiff peanut butter. These lakes region mice are very sophisticated and will not get caught dead eating cheap store brand peanut butter.
