Mouse holes in the wall can lead to a major infestation in your home in a short amount of time. To prevent mice from taking over your home, you must fill in the holes to keep them from entering. There are a few options for filling in mouse holes in your home that can either kill them off or allow them to live, depending on which you prefer.
Fill the mouse hole with steel wool. Pack the hole tightly with steel wool to prevent any possible entrance through the hole. Mice will eat the steel wool, which will kill them. However, the mice may die in the wall, causing an unpleasant odor in the home while the body decays.
Fill the hole with steel wool, and cover the steel wool with silicone caulking. The steel wool will clog the hole, preventing the mice from passing through the hole. The silicone caulking will prevent the mice from eating the steel wool and dying in your walls.
Fill the hole with expanding spray foam. Once the foam expands completely, cut away excess foam protruding into the room. The foam will keep the mice from entering the room for awhile, but they may eventually break through the foam if they really want to get inside. Consider placing mice poison inside of the hole before spraying the hole with foam.