Mothballs are an unreliable and potentially hazardous choice for keeping rats away. Use them only for the purpose and conditions stated on their label, and tackle rodents by dealing with food, access and nesting places.
Why people think they work
Mothballs release naphthalene, a strong-smelling chemical that rats do dislike. In theory, fill a space with enough of it and rats stay away.
Why they don't
The catch is in the word "enough." The concentration of naphthalene needed to drive rats out is far higher than is safe to have in a home. At the small amounts that are safe, a determined rat tolerates the smell to reach food or shelter. So you are left with a faint odour that does not solve the problem.
And they are a real hazard
Naphthalene is toxic if inhaled in quantity or swallowed, a real danger around children and pets, who may mistake mothballs for sweets. The dose that might bother a rat is exactly the dose that becomes unsafe for your family. That trade-off alone rules them out.
Mothballs in the car? Even worse
Some people leave mothballs in the engine bay or cabin to keep rats away from a parked car. A closed car in the Indian sun gets very hot, and heat makes naphthalene evaporate faster, so the fumes build up inside the cabin you then sit in. Meanwhile, the engine bay is open to the air underneath, so the smell disperses before it bothers a rat much. It's the worst of both worlds. For what works in a car, see how to keep rats away from a parked car overnight.
Other home remedies, rated
| Remedy | Does it work? | Main problem |
|---|---|---|
| Mothballs (naphthalene) | Not at safe amounts | Toxic to people and pets |
| Camphor | Briefly | Smell fades within days; also unsafe if swallowed |
| Peppermint oil | Briefly | Needs re-applying every day or two |
| Chilli powder or flakes | A little, on the spot | Messy; doesn't stop rats going around it |
| Bay leaves, onions, garlic | Little evidence | Rats usually ignore them |
The pattern is the same for every smell-based remedy: strong at first, weak within days, and never stronger than the pull of food and shelter.
If a child or pet swallows a mothball
Treat it as an emergency. Take the child or pet to a doctor or vet immediately, and take the packet with you. Don't try to make them vomit unless a doctor tells you to. Signs of naphthalene poisoning can include vomiting, stomach pain, drowsiness and, later, pale skin or dark urine.
Getting rid of old mothballs safely
- Wear gloves, put them in a sealed plastic bag, and follow the label and local chemical-waste disposal advice.
- Don't burn them or flush them.
- Air out cupboards and rooms where they were kept.
- Wash clothes that have absorbed the smell before a baby or small child uses them.
What to do instead
- Remove the food: sealed containers, no crumbs, covered bins.
- Remove the shelter: declutter and seal gaps larger than 2 cm.
- Add a safe, lasting deterrent: one that does not depend on toxic fumes.
For do mothballs really keep rats away, the EchoRepel Home Rat Repellent is a supporting option using ultrasonic sound that rats and mice want to avoid. It is poison-free. For do mothballs really keep rats away, use the device only as instructed and assess new signs rather than assuming protection.
If mothballs are already scattered around the house
First stop children and pets reaching them. Keep the packet so you can identify the contents and read the handling instructions. Avoid sweeping loose balls into a dusty pile or transferring them into an unlabelled food container. If there is a strong smell or anyone feels unwell, leave the affected space and seek medical advice.
Check the product label and local waste authority guidance before disposal. Rules for chemical waste differ, so household rubbish is not a universal answer. Do not burn mothballs, flush them down a toilet or put them into an open garden drain. A sealed, labelled container awaiting appropriate disposal is safer than loose material in an accessible bin.
Replace the remedy with a specific repair
If you placed mothballs under the sink, inspect the waste-pipe opening and any leak instead. If they were in a wardrobe, inspect the back panel and wall junction without disturbing droppings. If they were under a car bonnet, let the vehicle cool and ask a workshop to recover anything that has fallen into an inaccessible area.
Write down what made you suspect rats in each location. Chewed packets, recurring droppings and a nest lead to different immediate tasks. A smell that masks those clues can delay the repair, so assess fresh evidence after the chemical source has been removed and the space safely cleaned.
Do not substitute another strong chemical
Pouring disinfectant, fuel, ammonia or concentrated oils around the same gap repeats the underlying mistake: treating an open route as an odour problem. Household products should be used according to their own labels, not combined into a homemade rodent treatment. Keep cleaners away from food, electrical equipment and hot vehicle parts. A pest professional can help choose a control method for an active infestation without relying on an unpleasant smell as proof that the area is protected.
For do mothballs really keep rats away, related questions include what smells do rats hate, how to rat proof your house.
Frequently asked questions
What if I cannot find every mothball under the bonnet?
Keep the car off and ask a workshop to retrieve inaccessible material. Do not reach beside hot parts, move wiring or start the engine to dislodge it.
Can I reuse a food jar to store loose mothballs?
Keep chemicals in their original labelled packaging where possible and follow its storage instructions. An unlabelled food container can cause a dangerous mistake, especially around children.
Does a lingering smell mean the room is still protected?
No. An odour does not establish rodent control or suitable exposure conditions. Follow label advice for ventilation and cleaning, and investigate the original entry route.
Can I hide mothballs inside a cloth pouch?
A pouch does not make an unsuitable use safe or turn the contents into a proven rat repellent. Follow the labelled use and keep the material inaccessible to children and pets.