Mothballs vs. Mice: What a Pest Pro Says Actually Works

Mothballs emit a strong, unpleasant odor, but they are ineffective in deterring mice. Despite this myth’s persistence, mothballs fail to keep mice out of homes. Understanding why mothballs don’t work can help us find effective methods to keep mice away both inside and outside the home.

What Are Mothballs?

According to the National Pesticide Information Center, mothballs, flakes, crystals, and bars are insecticides. When used in an airtight space, the balls slowly give off a strong gas that permeates the air and kills moths, silverfish, and other fiber-eating pests that destroy wool clothing.

They do not repel wildlife like mice or other rodents and there are much less toxic ways to control clothes moths.

If handled excessively, ingested, or if a person is overexposed to mothball vapors, the ingredients are toxic according to the National Poison Control Center.

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Can You Use Mothballs to Keep Mice Away?

“People often use mothballs in inappropriate sites and against incorrect pests,” Stock says. “Unfortunately, mothballs are used to control pests other than clothes moths, including squirrels, mice, rats, and a variety of other animals.”

The myth that mothballs will keep mice away persists because some groups classify mothballs as rodenticide, or chemicals that kill rats and mice.

If a rodent consumes enough mothballs, it can die but as long as there are other food sources around, rodents are not going to eat mothballs. Mothballs are not a deterrent for rodents.

Indoors

Besides moths, the only thing mothballs are offending is people. The odor is strong and permeates clothing and the air. Mothballs are also dangerous to pets, children, and vulnerable adults if they are handled or ingested because they look like a ball of candy.

Outdoors

The myth persists that using mothballs outdoors will repel rodents, squirrels, bats, snakes, or other wildlife from entering a home or destroying a garden. Mothballs are ineffective for this use and can contaminate soil and water.

12 Ways to Actually Keep Mice Away

Now that you know that mothballs just don’t work, here are some ways you can actually keep mice away from inside and outside your home.

House mice are one of the most common and bothersome rodents in the United States. They consume and contaminate food meant for humans, pets, livestock, or other animals and cause considerable damage to structures and property.

If you already have an infestation of mice, use snap or humane traps placed in strategic locations near rodent activity.

Indoors

• Seal any openings larger than one-fourth inch to keep mice from entering. Steel wool makes a good temporary plug until you can tightly seal cracks in walls or floors and gaps around water pipes, vents, and utilities.
• Be sure doors, windows, and screens fit tightly. Remember that mice can gnaw plastic sheeting, foam rubber, and even wood.
• Keep a clean house. Store foods in air-tight containers made from glass and metal to keep mice away. Clean kitchen counters, sweep floors, and empty trash cans daily.
• Eliminate clutter. Mice love to have a place to nest and hide. Cardboard boxes are a favorite mouse haunt so get rid of them.
• Move stored items two to three feet away from exterior walls to decrease hiding places, Mice do not like to be exposed out in the open.
• Monitor pet feeding areas. Mice love dog and cat food—empty uneaten food and water dishes at night. Store dry pet foods in mouse-proof containers.

Outdoors

• Keep compost bins covered to prevent them from becoming a feeding ground for mice.
• Store bird seed in a mouse-proof container.
• Seal foundation gaps. Cracks and gaps in the foundation of a home are a direct conduit to the interior of your home.
• Keep trash cans covered to keep mice away.
• Get rid of clutter. Piles of junk provide a perfect warm, nesting place for mice and other rodents.
• Keep stacks of wood and plant materials at least three feet away from exterior walls to lessen access into the home. Remove vines that are climbing up the house, since mice are excellent climbers.