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Do Mothballs Keep Mice Away? Or Is that an Old Wives’ Tale?

Do Mothballs Keep Mice Away? Or Is that an Old Wives’ Tale?

Rodent control. It’s something all RVers need to think about at one point or another. As winter approaches and the little critters are looking for places to nest for the winter, we’re looking at an age-old question: “Do mothballs keep mice away?”

Those pesky little critters find ways to stow away in our rigs during camping trips in areas where mice are prevalent or when our rigs are stored for an extended period of time.

We’ve posted previously about how to keep invasive mice out of your RV for good. But today we’re focusing on whether the idea of mothballs repelling mice is based on fact or just an old wives’ tale.

Do mothballs work? Let’s find out!

What Are Mothballs?

Mothballs are small white balls made of either naphthalene or para-dichlorobenzene. These toxic chemicals are solid at room temperature and over time they change to a gas that becomes strong-smelling toxic vapors.

Mothballs are toxic to humans and pets so they need to be used with extreme caution.

Why Are They Called Mothballs?

Mothballs were originally developed to address the problem of fabric-eating moths damaging clothes that were stored away.

Moths or moth larvae would create holes in garments that were stored for longer than a month or so. The idea was to toss a few mothballs into a drawer or storage chest. The poisonous vapor emitted from the mothballs would kill moths and their larvae, preventing the problem of the fabric being chewed.

So, mothballs were used as a form of pest control, and they earned their name from the fact that they originally targeted moths.

Do Mothballs Get Rid of Mice?

If you’ve ever had mice in your home, you know they can be very difficult to evict.

Mice can take up residence fairly easily because our homes and RVs have multiple entry points they can slip through very easily. 1/4 inch is all they need. One-quarter of an inch! For reference, that’s about the size of a pencil eraser.

Whether or not mothballs can get rid of mice is a different question than whether they’ll keep them away, though. If you’ve already got a mouse problem, mothballs are unlikely to be what you need.

While naphthalene can be a deterrent in large quantities, the amount of naphthalene in mothballs is not enough to get rid of mice and other rodents.

Instead, you may want to pick up some of these:

Tomcat Press 'N Set Mouse Trap, Plastic, Spring-Loaded Mouse Killer with Grab-Tab, 2 Traps
  • Tomcat Press 'N Set Mouse Trap effectively kills mice with one simple set of the trap, guaranteed*
  • Our plastic, spring-loaded snap traps are easy to set and reduce the risk of pinched fingers

Alternatively, you can have a look at our video on how to make an emergency mouse trap. (YES – this really works!)

Do Mothballs Keep Mice Away?

According to pest control professionals, mothballs are not an effective deterrent to mice.  They note that while the amount of naphthalene is sufficient to address moths on fabric, it is not sufficient to deter mice and rats.

Moreover, we’ll repeat that naphthalene is toxic to humans and pets and isn’t environmentally friendly. Children or animals coming in contact with mothballs could ingest them, so they’re actually quite dangerous to have around your home or RV.

Exposure to naphthalene can damage blood cells. This can lead to hemolytic anemia, a condition that has been found in children who have eaten mothballs.

We do know that rodents tend to have an aversion to strong smells, however, so essential oils (which smell much better than mothballs) would be a safer way to introduce strong, repellent odors around your RV! Many RVers report that peppermint oil on cotton balls can be enough to deter mice. 

While we know that this hasn’t worked for everyone, even pest control professionals recommend the use of strong smells like peppermint or clove oil, ammonia, cayenne pepper, mint toothpaste, dryer sheets, vinegar, or tea bags.

You’ll hear many people claim that those smells are excellent deterrents, and you’ll hear many others claim that the mice loved the smells and made nests with the dryer sheets, ate the soap, etc. Different strokes for different mice, apparently!

Many RVers swear by the product Fresh Cab which is non-toxic, environmentally friendly, and actually smells great (to humans).  About 80% of 9,000 Amazon reviewers say it works. About 7% say it’s a mouse snack. Your mileage may vary.

Fresh Cab Rodent Repellent - Botanical Pest Control for Indoor Use - Safe for Kids & Pets When Used As Directed - Made with Plant Fibers, Balsam Fir Essential Oil & Fragrance - 4-Pack
  • Botanical Pest Control: Lab-proven to repel rodents swiftly and efficiently
  • Mice Repellent for Your House: Designed for indoor use

Have You Used Mothballs to Keep Mice Away?

Since there isn’t one solution that seems to work for all mice/situations, let us know what you’ve used to keep mice at bay and how well it has worked for you!

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Monday 3rd of October 2022

During Winter storage, I put poison bait on top of the tires and an open container of mothballs inside. So far, 9 Winters, no mice. We thoroughly clean after every trip and rig is always outdoors.

Steve Lamb

Tuesday 20th of September 2022

I don’t know if you have ever met Sean and Kristy in your travels but this is pretty funny! ~ Steve

Larry B

Tuesday 20th of September 2022

We have had our used 2006 vortex toy hauler for three years and NO mice. Our "trick" is to clean clean clean. If there is no food even small scraps you will have no mice. Just clean up everything as soon as it spills or is dropped. This works in our house too. It is really worth the effort.


Wednesday 21st of September 2022

Apparently, cleanliness is next to mouse-less-ness, Larry! ????


Tuesday 20th of September 2022

Mice /Rats have good sniffers. They use them to find all kinds of stuff including where they have been. I have used the mothballs in plastic bags and it has been effective under the hood IF you clean their mess before adding the mothballs. That way they think their in a new area and not so likely to hang around.The best way I have found to keep them away is to light up the area. I use rope lights under the hood (engine area) and ground area near by and connect them to a Dust-Dawn timer. I live in the Arizona desert area and this has worked for me for many years.


Wednesday 21st of September 2022

Thanks for sharing, TC!

Neal Davis

Tuesday 20th of September 2022

We have tried numerous things and none seemed to work. Moth balls, essential oils, dryer sheets, Irish Spring shavings, rope lights, and plug-in lights/sound emitters have all failed to do much. Galvanized wire mesh glued over openings prevented entry into some areas, and conventional mouse traps and glue traps caught some. But they still got into the RV. Thankfully they only chewed paper, peed, and pooped, never chewing on wires, causing faults, or worse. We now have encircled our RV barn with wide (20") roof flashing and covered the ground around the barn with a wide (24"), thick (4" deep) layer of pea gravel to prevent tunneling into the barn. We hope this will protect Newton the [2022] New Aire [3545]. If not, then we'll do more.


Wednesday 21st of September 2022

Oh, wow, Neal! You've got some persistent little rodents around you!! Fingers crossed the new barriers do the job!

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