How to Keep Mice Out of Cars, RVs, Boats, Motorcycles & Farm Equipment

Keeping mice out of your cars, RVs, boats, farm, lawn tractors and mowers, and ATV vehicles is an endless battle. I’ve collected the best advice on what repels mice specifically in vehicles. These tried-and-true stories from real people offer valuable insight of what repels mice naturally.

I don’t have to tell you that mouse pee/urine causes corrosion, rodent chewing damages interiors, as well as causing thousands of dollars in damages to wiring/wiring harness (due to their attraction of soy-based plastics coating of the wiring).

Wherever you park or store your vehicles, whether it’s the great outdoors, a garage, shed, or boat, there is hope to expel mice.

DISCLAIMER: Much of this rodent deterrent advice is anecdotal. In my research I found users that proclaimed overwhelming success, while others failed. I will take personal endorsements any day when it comes to keeping mice out of my cars, RVs, and other vehicles!

Table of Contents

• Preventative Measures to Keep Mice out of Car, Motorhomes, Boats and More
• Light & Movement Keep Mice Out of Cars, RVs & Tractor Cabs
• Using Sound to Keep Mice Out of Cars, Campers
  • Keep Pests Out of Sheds, Gardens, & Goldfish Ponds
  • Best Ways to Use Sounds to Deter Mice
• From the Kitchen: Natural Mouse Deterrents in Vehicles
  • Mouse Deterrent Recipe for Engines:
  • Where to Spray Peppermint Oil on Car & RVs
  • Does Peppermint Oil Deter Mice?
  • What to Mix Peppermint Oil With?
  • Natural Mouse Deterrent Warnings
• Spicy & Hot Natural Mice Deterrents to Keep Mice Out of Vehicles
• Household Products That Keep Mice Away from Cars
  • Do Mothballs Keep Mice Away?
• How Long Does Essential Oil Scent Last (and Other Natural Mouse Deterrents)
  • Tips for Using Natural Mouse Deterrents
  • Natural Deterrents That Are Harmful to Pets
• Physical Deterrents to Keep Mice Out
• In Conclusion

Preventative Measures to Keep Mice out of Car, Motorhomes, Boats and More

First off, the easiest thing you can do to keep mice out of cars:

• Keep food out of your car and farm tractors!
• Wash up beverage spills and vacuum out crumbs that can attract rodents.
• Don’t park car or truck inside a garage where garbage is (this includes pet food or livestock feed).
• Park away from dumpsters that attract mice and rats.
• As soon as you smell mice in a car, spray natural deterrents around the car and under the hood (before they get comfy and have babies!).
• For camping enthusiasts, bring ammonia or peppermint oil and use it everywhere you camp each night, spraying under RV hoods and vans, and under them on the ground (or soak paper towels to put underneath).
• Place deterrents at entry points, such as car tires.
• When parking at your campsite, open the hood for awhile to dispel the heat (mice love warm and cozy spots!).
• Make sure you have the car vent mode in recirculation mode to help prevent rats/mice entering the passenger compartments.
• For vehicles, boats, RVs in storage for winter: open all cabinets, compartment doors, etc. Cover any grill openings that have access to compartments, lift cushions up or remove cushions and store inside home.
• Set out bait, mouse traps, or pail-style traps as a barrier to stop the mice from getting to your car, motorhome, farm equipment, lawn mower, etc. Be generous with the quantity and placement (like the four corners of a shed).

Chasing mice out of the car is probably easier than trapping a mouse in a car. Use best practices (natural mice repellents) to prevent mice from getting into your car in the first place. I have heard of desperate people attaching sticky traps inside of the car hood/engine area, and mouse traps inside of the car. Desperate times call for desperate measures.

Sticky traps would be a last resort – the general consensus is that they are inhumane.

Light & Movement Keep Mice Out of Cars, RVs & Tractor Cabs

There are many rodent-catching endorsements of using light and motion to keep mice out of cars, RVs, and other vehicles. Using lights in combination with sound strategies is a good duo.

I would caution playing music around chickens during night time hours that could disrupt sleep patterns and egg laying production. Chickens love to eat mice (and snakes, too!), so they’re part of your “keep mice out of shed” team! If you have a bigger infestation, than you will need to apply a combo of strategies. Rats are probably too big for chickens to handle.

The only downside of using lights is your electric bill. You will have to decide how long you feel you need to implement keeping the mice out of your cars and campers with this technique.

Here is how the experts are doing it:

• Install motion detector lights around parked vehicles/vehicles in storage.
• Use solar lights around perimeters of vehicles.
• Place blinking Christmas lights (in attics, crawl spaces, stored vehicles such as your vintage cars in storage and farm tractors).
• Use strobe lights to keep mice out of tight spaces (as well as squirrels).
• Leave the vehicle hood up in garage, with the garage light on (this goes for riding lawn mowers, too).
• Honk the horn to scare mice away.
• String up milk jugs to branches and let the wind rustle them.
• Novel solution: set roomba to run at night.

Using Sound to Keep Mice Out of Cars, Campers

The use of radios and other noises can be used for both longer-term and short-term strategy. In the case of short-term, blasting sound can chase animals out of holes, from under buildings, and forcing them out of attic and crawl spaces.

Keep Pests Out of Sheds, Gardens, & Goldfish Ponds

It’s not just for mice, blasting music deters racoon, ground hogs, skunks, squirrels, fox, and coyote. This advice comes from farmers and homesteaders who might also be trying to keep mice/rodents and predators out of chicken coops or away from free-ranging chicken (again, I don’t think the chickens would appreciate the music at night!).

Radio keeps deer out of vegetable garden and racoons out of sweet corn patches. One guy mentioned he had the radio protecting his garden every night, but forgot one night and the racoon wiped them out. One person mentioned keeping a radio on keeps racoon away from her goldfish pond.

Another user proclaimed, “Turned the garage radio on over 20 years ago and have never seen signs of rodents. Had to finally buy a new radio!”

Best Ways to Use Sounds to Deter Mice

So if you’re interested in chasing animals away from tractors, lawn mowers, ATVS, and cars and campers stored in out sheds, consider going loud with the noise!

• Talk radio/NPR seems to be the most popular, but it’s good to change the music up.
• Use MP3 player on loop with people talking.
• Drop a bluetooth speaker in hard-to-reach places like heating ducts and attics.
• Keeping a radio on also helps as a deterrent for burglers.
• Leave radio on low at night when you leave your shop or garage.
• Run a vacuum cleaner hose into a hole and leave running for awhile to chase off skunks.
• Place a smoke alarm with weak battery – it will beep for months (suggested by a junkyard owner who puts in cars he wants mice to stay out of).
• Play music, either from car stereo or set up radio near your vehicle.
• Electronic or ultra-sonic mouse deterrent. These devices emit sounds at a high frequency that don’t appeal to mice. I do NOT endorse these. Too many people have been disappointed in their effectiveness.

From the Kitchen: Natural Mouse Deterrents in Vehicles

Your kitchen and pantry hold a plentiful list of natural mouse deterrents. From plants that repel mice, to spicy foods that mice don’t like, we’ve got you covered. For mixing mouse repellent recipes, pick up a Zep Professional Sprayer Bottle for the best spraying experience or invest in a cheap pesticide sprayer for broader applications. Diffusers also work as a bug bomb fogger.

Cotton balls are also a go-to choice for soaking up peppermint oil. One mouse-fearing user advises to “use a BOWL of cotton balls, not just one!”

TIP: If using natural mouse deterrent like peppermint oil in your RV, motorhome, or camper/pop-up camper, store the oil-soaked material in large ziplock freezer bags until next year to reuse again. Leave camper open a day or two to air out. Users report that soaking the peppermint oil in wool or dryers sheets retains the scent longer.

• Onion and garlic. One person suggested placing an onion on glass (mice don’t like glass)
• Mint and peppermint plant. Some people plant around perimeter of house.
• Peppermint oil. This is a highly endorsed mouse deterrent.
• Cinnamon.
• A combo of lavendar + generous helping of ground cloves + citron oil
• Mist a combo of peppermint oil and cayenne pepper spray.
• Bay leaves (they may even cause death to mice is ingested)
• Spray vinegar
• Lemon grass oil
• Cayenne Pepper, Hot Pepper Flakes, etc. (jump to a dedicated section on that below).
• Mouse mouse repellent pouches. One woman says she never throws these away, only spritzes on peppermint oil and reuses them.

Mouse Deterrent Recipe for Engines:

Mix and pour into small squirt bottle: water, tablespoon of peppermint extract, couple of drops of dishwasher liquid soap or rubbing alcohol (10 drops to 1 teaspoon of alcohol and then add to the water). Dawn dish/rubbing alcohol help the peppermint oil remain mixed with the water. Spray in engine compartments to combat wire-nibbling rodents (great for non-food areas of your grill, too – smells great to humans, not for mice). To get the oil to mix more easily, create an emulsion with a little bit of peppermint castile soap in warm water with the peppermint oil and shake it up.

Where to Spray Peppermint Oil on Car & RVs

The primary entry point for mice will be running up the wheels of the car and up the shock absorbers (although mice can jump). Mix a spray bottle of peppermint oil up and spray anything that isn’t electrical, or belts, or struts (just outer rims of tires).

Also consider soaking a cloth in the peppermint oil and placing in a thick plastic bag, poke few holes in it and duct tape it at the top under the car hood, right under the windshield; refresh every few months.

Another line of defense is infusing cardboard or cloth with peppermint oil and placing it under your car or RV vehicle to stop mice. The guy below gives a thorough demonstration on spraying his car, in case you’re nervous of where to spray.

Does Peppermint Oil Deter Mice?

Peppermint oil, cayenne pepper, pepper and cloves are all natural mouse deterrents. Give them a try! Unfortunately, bears love peppermint oil, so beware! Tea tree oil is not recommended in bear inhabited regions, either.

What to Mix Peppermint Oil With?

Although peppermint oil can be mixed with water, consider mixing it with 70% alcohol. This applies to any kind of essential oil. The alcohol disinfects and evaporates faster. Users report that the alcohol seems to carry the mint oil better, making the scent dissipation spread fast.

DIFFERENCES BETWEEN PEPPERMINT OIL: There are two types of “peppermint” oil sold…both come from the plant Genus Mentha. These two are Mentha piperita and Mentha arvensis (Corn Mint). The one you want is Mentha piperta. It costs about twice what Mentha arvensis costs, but it is the one recommended for use as a rodent repellant. If a product doesn’t clearly state which oil it is, you can assume it is the less effective/cheaper oil….and it usually has some bad reviews. @carlwelte6094

For me, mentha arvensis on cotton balls in our cars has been successful at deterring mice. Perhaps it’s because of the quantity I use. Typically, I’ll put six soaked cotton balls in the engine compartment, 2 or three in the trunk and two inside the cabin. This is a lot more product than this youtuber used with his spray bottle. Perhaps I’ll try the more expensive mentha piperata and use less, or I’ll try the spray method in the video.

Natural Mouse Deterrent Warnings

I was surprised to find this package of natural rodent repellent in my pest control stash. One of my family must have picked it up free at a farm meeting. It has a strong smell of cloves, on the package it reads “balsam fir oil.”

Natural pest deterrents should never be stored near poison (or chemicals, gas, and other strong-smelling things). The poison will absorb the smell of these products. The poison then turns into a deterrent and mice will avoid the poison.

I relate the same thing happening to flour, which also has a tendency to absorb smells, such as scented laundry detergent. Anything you bake with the flour will taste like the detergent.
See below where I address mouse deterrent strategy in farm equipment, and why it is so important. This company labels the product “Fresh Cab” because it is targeted to farm tractor cabs – mice are a real problem in any vehicle transporting grains.

Spicy & Hot Natural Mice Deterrents to Keep Mice Out of Vehicles

If you’re not having luck with using hot mice deterrents like pepper flakes and hot sauce, it might not be hot enough! If you want to bump up your mouse deterrent game, you need to learn about Scoville units

A Scoville unit is a measure of the pungency (spiciness or “heat”) of chili peppers, based on the concentration of capsaicin, the compound that causes the burning sensation.  It’s a unit used in the Scoville scale, which ranks peppers from mildest to hottest. The higher the Scoville rating, the hotter the pepper. 

Here are some recipes/combos to follow, but TAKE PRECAUTION. Always handle hot products with rubber gloves and avoid touching your face (or private parts – that’s another story regarding and emergency room visit!). Peppers can even cause strokes, especially for virgin mouths.

According to Magic Plant Farms, a flake versus a powder has more surface area, giving more surface area to the mouth: “When you bite into a flake, the pressure physically ruptures the remaining pepper cells, instantly releasing pockets of capsaicin onto your tongue. This is why flakes can feel hotter than powder, even if you are using the same weight or volume.”

For the spiciest picks, you will want to consider Caroline Reaper Pepper, a super-hot chili developed in South Carolina. The California Reaper Pepper is not far behind, still in the development stages, but look for California Reaper Pepper Flakes to hit the market soon. And then of course there is Ghost Peppers.

The Carolina Reaper averages a scorching 1,640,000 units, with some tests showing peaks over 2.2 million. To put it into perspective, it’s 10 times more powerful than a habanero. Cayenne peppers typically range from 30,000 to 50,000 Scoville heat units (SHU) according to Chili Pepper Madness.

How Does Cayenne Pepper Deter Mice? According to Bug House Pest Control, “The theory is that the strong, pungent smell and spicy nature of cayenne pepper irritate a mouse’s sensitive nose and taste buds, encouraging them to avoid the treated areas.” Having the rodents step on it and then accidentally rub their eyes/face is secondary.

• Mix 2 T Carolina Reaper pepper powder mixed with cheap table salt in a shaker and spread around perimeter, base of buildings, etc.
• Red pepper flakes
• 1-2 T of hot sauce to 4 gal backpack sprayer, if large building – you want hot sauce over a million Scoville units.
• Sprinkle Cayenne pepper around house – mice can get into new houses, too!

Hot Pepper Recipe to Deter Mice in Cars & RVs. Mix equal parts of red hot sauce and vinegar. Use 2 cups of this mixture to a gallon of water. The hotter the sauce the better. The cheap, generic stuff works – as long as it’s hot, it works fine. Optional: add an ounce of light cooking oil and a teaspoon of dish detergent for adhering. If the sauce is too thick with particles, strain using a cheese cloth. You can make stronger or weaker, but it should have a spicy hot pepper smell to it.

Put the final mix into a sprayer and spray the entire underside of the vehicle and inside the wheel wells. You can use in the engine compartment too. Don’t use in any of the vents. It will wash off after a hard rain and driving.

Household Products That Keep Mice Away from Cars

Farm equipment that harvests grains also attract mice. Recently, the raccoons have damaged wires in the combine causing lots of damage – good thing we checked that well ahead of the harvest season. Mice will climb all over the equipment, finding any loose grains or corn.

My guys have always sprinkled mothballs in the tractor and combine cabs. From what I’ve been reading, vehicle owners are using entire boxes of dryer sheets for the same. I’m definitely not using as much as I should be, so think about that when spreading out these household mouse deterrents.

Here are popular suggestions to keep mice out. With all chemicals, DO NOT MIX THEM TOGETHER! We want to deter the mice, not kill you!

• Dryer sheets! Stuff generously and everywhere. Mice have very sensitive noses and don’t like perfumed dryer sheets. 
• WD-40 sprayed onto engine parts and wires.
• Tea Tree Oil (stronger than peppermint oil). Spray solution: Mix 10–15 drops of tea tree oil with 1 cup of water and a teaspoon of dish soap. Spray around car:
• Spray solution: Mix 10–15 drops of tea tree oil with 1 cup of water and a teaspoon of dish soap. Spray around parked vehicles – great for your home along baseboards, under sinks, and near food storage.
• Another novel mouse deterrent hack is using Comet or Ajax cleaner. I’ve heard of folks sprinkling a circle around the outside of their camper when they put it away for the season. Of course, be aware of accidental pet access.
• Mothballs around engine (you can put in car or tractor cab or semi cab, but then that compartment will smell like mothballs.
• Put a moth cake into a tube sock, and tie the sock around the filler neck of the washer fluid.
• Menthol mouse detterent or jars of Vicks Vapo Rub (this came from a motorcycle owner). Drill holes in the lid and place 1 jar on engine between cylinders, one on front of engine next to filter, and one on seat under the covers.
• Sharply scented gel air freshener pads.
• Irish Spring Green or Sports Blue shavings in panty hose or jewelry mesh bags.
• Spray ammonia generously, or poke holes in plastic water bottles. Place ammonia-soaked rags inside of plastic water bottles or fill a tin can half full of ammonia. Keeps rabbits and squirrels out of your garden as well.
• Spray full-strength Pine-Sol around lawn mower engine.
• Spread cedar shavings/mulch around RV, pop-up campers, trailers, etc. in storage.
• One woman reported that sprinkling peppermint oil on bounce dryer sheets held the scent better; another woman said wool absorbs and holds the scent better.

TIP: Spray pepperminit/mint sprasy on a sheet of cardboard and slide under the parking spot of RVs, campers, motorhomes, travel trailers, cars in storage, lawn tractors.

Do Mothballs Keep Mice Away?

Mothballs were my mother-in-law’s go-to for keeping the mice out of the grain combine machine. However, according to The Family Handyman, mothballs are ineffective — and not safe at keeping mice away.

Despite the strong smell, mothballs are not a reliable mouse repellent. They contain chemicals like naphthalene or paradichlorobenzene, which are designed to kill moths in airtight containers — not repel rodents in open spaces. While mice may dislike the odor, the concentration needed to deter them is dangerously high and not safe for humans or pets.

Health & Legal Risks

Toxic fumes can cause headaches, nausea, and respiratory issues.
Illegal use: Using mothballs outside of sealed containers or for pest control violates EPA guidelines.
Environmental hazard: They can contaminate soil and water if used outdoors.

How Long Does Essential Oil Scent Last (and Other Natural Mouse Deterrents)

Here’s a detailed comparison table of common household items used as mouse deterrents, including how long their scent typically lasts before needing to be refreshed.

The scents can lose their potency over time and need to be replaced. If outside, rain can wash away applications. Spray shed and garage with peppermint oil every few months to restore potency.

Here is a comprehensive list of suggestions from homesteaders and farmers to keep mice out of their sheds, garages, and shops where RVs, classic cars, and tractors are stored:

Item	Effectiveness as Deterrent	Scent Duration Before Refresh	Notes
Dryer Sheets	Moderate (anecdotally effective)	Every 1–2 weeks	Strong scents like lavender or peppermint work best; place strategically.
Peppermint Oil	High (widely supported)	Every 2–7 days	Use on cotton balls or in spray; scent fades quickly, reapply often.
Bay Leaves	Low to Moderate (limited evidence)	Every few days	May deter some rodents; replace frequently for scent potency.
Vinegar	Moderate (natural repellent)	Every 3–7 days	Use undiluted or in spray; disrupts scent trails, but fades quickly.
Onion	Moderate (strong sulfur scent)	Every 2–3 days	Use fresh slices or peels; scent dissipates fast and can rot.
Pine-Sol	Moderate (strong pine scent)	Every 3–7 days	Use diluted spray or soaked cotton balls; scent fades over time.

Tips for Using Natural Mouse Deterrents

• Combine deterrents: Layering scents like peppermint oil with vinegar or Pine-Sol can increase effectiveness.
• Target entry points: Focus on baseboards, under sinks, behind appliances, and known rodent paths.
• Refresh regularly: Most natural scents fade quickly, so consistency is key.
• Extend potency length: One user recommends applying peppermint oil drops to dryer sheets, another person says the peppermint scent has lasted longer if applied to wool.

Natural Deterrents That Are Harmful to Pets

• Mothballs
• Ammonia
• Peppermint Oil
• Clove, Cinnamon, and Cayenne Pepper
• Eucalyptus Oil

Physical Deterrents to Keep Mice Out

On to the physical items that will keep mice out of stored cars, RVs, motorhomes, campers, pop-up campers, boats, motorcycles, lawn tractors, etc.

• If you have used cat litter (not the poop, only the piss) you can sprinkle it around vehicles if you’re really desperate! Can use pine litter too – also effective for keeping pests out of the garden.
• Spray area with predator urine – fox or coyote works best with mice.
• Set up an electric fence (not great for mice, but good for racoons who have tried to get into our farm combine!
• Drive your vehicle on a wire mesh or chain link fence and then electrify the mesh for vehicles in storage.
• Use a car storage bag (also known as a car bubble or car jacket). They are designed to keep humidity and rodents out.

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In Conclusion

Fighting mice in vehicles is an ongoing battle. They’re smart, but you have to be smarter. Sometimes the trick is swapping out methods, because what worked one season doesn’t work the next, or the mice become immune to it.

Stay strong and keep fighting those nasties!