How to get rid of mice? Did you know that mice can pass through an opening the size of a #2 pencil? No wonder they have an easy time entering our homes. By not doing anything about these small holes we are in essence inviting them inside. Mice come in first for shelter then for food. Have you ever had mice and wondered what they’re eating? If you can’t tell what they’re eating then that’s very significant. That means that they are having dinner somewhere else then coming back to your place to hang out. In other words they are coming and going as they please so you most definitely have openings that have to be plugged up.