Keep Rats Out of Your Car With Moth Balls.





Introduction: Keep Rats Out of Your Car With Moth Balls.

Living in a rural area has it's charms such as seeing deer grazing on the lawn on frosty winter mornings or staring up at the milky way on cloudless nights without the light pollution of big cities. Rats, however are not among those charms.
Every winter the rats seek shelter in the walls and attic of my home and, for whatever reason, this year has been worse than it has been for a long time.
Normally they don't pose much of a problem but now there are so many of them that they need to take shelter anywhere they can, including inside the engine compartments of our cars.
First up was the BMW about two months ago with a blinker going out and the check engine light coming on so we took it to the shop and nearly $3000 later all the wires the rats had chewed up were repaired.
Since that car had been in the garage I assumed that was the reason the rats had gotten up into it for further protection from the cold.
Well you know what they say about people who things... So a couple weeks later the light comes on in the Explorer and a few days later it starts running really rough and gets a trip to the dealer. Thankfully, that one was only $700 in damage.
So before the Accord became the next victim I decided to try to do something about it.

Step 1: Plan of Attack.

Poison or traps didn't really seem like a viable option since two of the cars are outside, and I had heard from several sources that dryer sheets under the hood would help deter them, but that seemed kind of sketchy as well. How do you attach them under the hood so they dont fly away? How long do they last? How many do you need to use? I have no idea, so I turned to the trusty ol' internet in search of alternatives and it seems that aside from dryer sheets many people believe in the use of moth balls for the same purpose.
So I went out and got some, now how to stick 'em in the car so  that they stay...

Step 2: Materials.

I had some excess screen laying around from replacing a tattered window screen and that was basically the inspiration for this enclosure I am showing you how to make. If you don't have any, you can get a roll of it at the hardware store for a couple bucks, or just use your imagination and see what you can come up with as long as the material provides good air flow and is somewhat strong.
Besides the moth balls and screen, all you will really need is a pair of scissors, duct tape, hole making implements, some wire (I used picture hanging wire), and a pair of wire cutters/pliars.

Step 3: You Wanna Make a Kinda Pouch.

I toyed with a few different ideas on how to accomplish this and finally fell back on the old faithful, duct tape!
Start by making a pile of both balls in the middle of a bit of screen, I cut mine to roughly a square foot but that's just because that was the width of the piece I had. Fold up the sides and corners until you have a little pouch that is flat on a side and tape it up. Just check out the pictures and you will understand.

Step 4: It's Hole Makin' Time!

Pick a nice juicy part and use your hole making implements to make a hole. I just used a hammer and a pointy thing that I think is meant for driving finishing nails into wood, but about any pointy thing would do.  After making a hole, flip it over and do the same from the other side and the duct tape will kind of cover ant frayed edges of the screen in the middle making a nice little tunnel.
Next, take your wire and run it through the hole, wrap it around and twist it off. Use the pliers to tighten the twists down until it's secure and then cut off something like an 8 inch lead or how ever much you think you will need for affixing the bundle.

Step 5: Find a Spot to Put It.

Pop the hood on you car and look around for a spot where there is a bit of room, no moving parts for it to get fouled in, and where it is relatively cool.

The Pictures are of my Accord; the first two are candidates for placement, and the third is an example of where not to put it because of the radiator fan and the exhaust manifold.

I decided to attach it to the airbox where it's somewhat protected from direct heat by the battery.

Step 6: P.s.

It's been a couple weeks now since I put these in all the cars and it seems to have worked to a certain extent. The moth balls disintegrate more quickly in the cars that get used more often so this design would be better for a car that is mostly just sitting.
Also, I noticed that is says on the box not to breathe the fumes. I don't know how dangerous it could be but the smell is pretty strong and you probably don't want to be breathing it all the time. As long as the A/C or fan is not on while driving there should not be too much getting into the cabin.



    • Stick It! Contest

      Stick It! Contest
    • Water Contest

      Water Contest
    • Oil Contest

      Oil Contest

    16 Discussions

    I can tell you from first hand experience of working in my family's pest control company that has been in business for 60+ years that moth balls have no effect on rats. If you want to try to keep mice away use mint oil on a cotton ball and replace it every 2-4 weeks. Not sure if rats will avoid the smell of mint. This is only a deterrent! If it always worked or if moth balls worked we would have been out of business a while ago. (P.S. I'm not saying its impossible for a rat to dislike the smell but on the whole don't count on this to work).

    2 replies

    Thanks for the input. After posting I found out that moth balls last an extremely short amount of time, and I have since switched to dryer sheets, but you are definitely right about anything only being a deterrent. I will try the mint idea next, if I can find it, as I am still finding evidence of the presence of rats in my engine compartment.
    I think the concept still holds though, it anyone wants to try putting something in the engine bay of their car it should be secured so it won't get loose and cause damage.

    NP. If your are looking for a physical barrier try copper mesh for a small area. Steel wool won't do anything but copper mesh will as it doesn't rust and they don't even like the taste. Try the Rat Zapper 2000 if you are looking for a reliable, effective and humane trap (it stuns and kills RATS in about 2 minutes, mice are instantly killed). Also don't keep any food around or give them a reason to be there. GL.

    spray Rataway Fragrance from saved customers over 8 million in damage since 1999


    1 year ago

    After reading through this I felt the need to comment. If you are solely relying on mothballs to stave off the rats, you will not solve the problem. Rats are extremely habitual. It seems like everyone is looking for the one stop solution, but you really need to hit upon the multiple sense of the rats in order to break their habit of going into your car, meaning strong smells, lights, and noises. Here is a great resource I found for more information:

    A GREAT way to make yourself really, really sick- the smell will come in the vents. DUMB idea. One we have used here in the Great Smokys of NC, in the boonie areas out of town where the mice think a vehicle is their own private apartment is We've used it for four years now, with no more chewing of wires, getting into the air system, or coming inside to chew everything they can and make nests. One bag goes into the glove compartment, one into the center of the air cleaner, and two up next to the firewall. 96 Suzuki Sidekick and 2010 Caddy SRX. Previously, we had lots of damage. Our neighbors still do. Replace once a year. If you live out west, where the rodents can be especially bad, try this one- you will have to run a cord out, so may have to hunt a battery operated device, instead (remember to remove that, every day, from under the hood as it is not waterproof-a PITA worse than running a cord for the other) . These devices have come a long way since their inception, and use varying pitches, so the creatures don't get used to them. We have used them successfully in our basement for mice, and on our A frame roofed deck, which has no screening, and was becoming a home for bats pooping all over the walls and floor. Nary a bat for three years now, and strangely, we used to have a horrible spider problem all over the ceiling- a PITA to clean at 18 feet high- but since using this, have none. No sprays used at all. Whatever you choose, I hope your problems are solved. All what I have written are from experience, not reading reviews of others.

    Avoid using mothballs in any occupied space where you can smell them. Mothballs are usually made of paradichlorobenzene (1,4 dichlorobenzene), a substance that damages heart muscle.

    We had a similar expensive summer of chewed wiring and have since gone to filling knee-high nylons (Walgreens sells them for $1 for 2 pr.=4 tubes) with mothballs, then knot or tie the tops and lay across engine anywhere there are wires or flat spots where they previously left their calling cards. No more damage for months now. Downside is you have to take them off before driving. We just pop them in a bucket next to car and replace them after we return home (after letting engine cool for a few minutes). Yes its a bother, but it only takes a moment to put them on and off, with the added benefit of not having to smell them while we drive. We also learned to leave a pair of gloves with bucket so WE don't smell of mothballs (smell is hard to wash off your skin!) Hope this idea helps someone out there :D

    I just found out that peppermint works very well. I have the herb growing all around my house to see where it will grow best. It can be dug up easily and moved around. Once you get a good crop, maybe a paper shopping bag full of leaves and some stems, you are ready! I crumbled some leaves around some peanut butter bated snap traps and the mice never touched them! They did go after the ones with no peppermint nearby. So it works! I read that the mint distorts their very sensitive sense of smell. The mice are not talking. But it makes sense. Try it. I used old pantyhose and tied bags under my car hoods, in car glove boxes, under seats. It smells nice too. So far no mice!

    1 reply

    Oh, I forgot, the mint herb family is a Perenial and can be planted in tubs and containers too. Mine dies back each fall and then grows back in early spring. Get some small plants and they will spread quickly. Take small clumps with roots and soil and plant in places around your home. It will grow just about anywhere. Enjoy!

    MOTH BALLS DON'T WORK! Try electronic pulsing devices made for bug and mice . I have them in my closets and garage. They have been working for 5 years! You must move them around every month or so, or the little beasties will get used to them and ignore them! I put mine on small extension cords and just move them at my leisure ! Add some snap traps, poison bait and the population will decrease! Works for me!

    They may work for engine compartments, but i can tell you now that they absolutely do NOT work in the attic. I dunno maybe the heat from the engine has something to do with it.

    Also, you can spray Rataway Fragrance non-toxc & non-poisonous to protect car engines and wiring. Use to protect cars, trucks, farm machinery, homes, business,etc... safe around pets & children

    Very nice instructable! We had a mouse get into the engine of our RV this fall, $1500 in repairs later, I also decided to try mothballs! My wife suggested using the plastic mesh bags that fruit comes in (like melons, etc). Other than that, we pretty much did the same as you... I hung my bags from hooks made from wire ties that come on bags of sandwich bread. I ended up with four bags around the compartment - that used up a box of moth balls.

    We did notice that when we removed the bags to drive somewhere, that they were pretty strong smelling. I tried putting them into a ziplock bag, but we could STILL smell them! I think they will eventually get a mayonnaise jar for storage when not in the engine compartment.

    Good job!