Home remedies for keeping mice away include placing cotton balls soaked in peppermint oil in areas where mice have been seen, and keeping resources such as food, water and shelter inaccessible. Mice are repelled by the smell of peppermint, so the cotton balls should be reapplied whenever the scent begins to fade.
Keep food in sealed, airtight containers. Clean up spilled food and dirty dishes immediately. If there are pets in the house, remove food and water from their bowls after feeding, and store all pet food securely where mice cannot reach it. Clean the house regularly with soap and water, dispose of garbage in a timely fashion, and keep all garbage in rodent-resistant receptacles.
Cover all vents and drains leading from the home in a fine mesh screen. Examples of potential entryways include attic vents; ridge vents; heating, venting and air conditioning drains and vents; and dryer vents. Gas vents and exhaust vents in the kitchen or bathroom may also be potential points of entry.
If the mice are entering through holes in the wall, plug the holes with steel wool. To locate entry points and exits, sprinkle flour on the floor and follow the footprints. If mice can enter under a door, it may be necessary to install door sweeps.