Set up a half to three-quarters full 5 gallon bucket (or something) with water, near where your mice or chipmunks are.  Mice or chipmunks can be near your garage, your woodpile, your garden or around your house.  With chipmunks you often see their burrows.  Mice are mostly night time animals, chipmunks are daytime animals, so their paths don't normally cross.  Make sure the amount of water will not be deeper than your pet dog or cat cannot stand in or get out of. Place a ramp up to the top of the bucket and sprinkle birdseed or sunflower seeds up the ramp and into the bucket so they float on top of the water.  They jump right in! This method has been used for many years, it works pretty well. Make sure you float enough seeds so that they disguise the reflectivity of the water. You can also float a bunch of corks on top of the water, it masks the water and won't support them when they fall in.  (The corks are an old exterminator's trick, we always have corks on our trucks, they're used for other things.) To hasten the process of drowning, squirt some dishwashing soap in the water. Also put just a few (THAT'S ONLY A FEW) of those seeds leading up your ramp.  You want him curious, not satisfied. Fish out the expired animals at least once per day and change the water every two or three days.  You can bag the animals and place them in your trash. And, no, this trick will not work on adult rats, they are generally too smart to fall for this.  A young and inexperienced rat might, however.