Mice are smaller than rats and can consequently can find easier access into your home. They can squeeze through quarter-inch cracks and holes and will slip through spaces between pipes and wiring, and gaps between walls and foundations. They can destroy personal property, contaminate food and belongings and gnaw at wiring and insulation, but steel wool can be used to seal even the smallest points of entry.
Inspect for signs of mouse infestation. Be alert to mouse droppings, sounds of scratching behind walls, gnaw marks on wood and baseboards, oily smudges on walls and signs of nesting. If any of these signs are present inside your home, you will need to set traps to catch rodents already in residence.
Carefully cut steel wool. Wire wool strands are razor sharp and can cause nasty cuts. Wear gloves and use care when cutting steel wool to size for a particular spot.
Cram steel wool into holes, cracks and gaps in walls. Pack tightly, leaving no gaps. If mice chew at steel wool it will cause internal bleeding and kill the mice.
Caulk around steel wool after you fill gaps. This will reinforce the seal and may prevent mice from chewing the steel wool and dying. Dead mice in your walls can leave a putrid odor.
Mix steel wool with mortar and fillers to make them mouse-proof. Mortar and other fillers can be pulled out by a rodent's strong, hooked front teeth. Using steel wool in conjunction with these materials for repairs and patches will make them impenetrable by mice.