How Mothballs Work and Where They Can Be Used Legally

If you are searching for how to properly use mothballs, you are probably dealing with stored-clothing protection or an unwanted pest problem that keeps coming back. The catch is that mothballs only work when the vapor stays trapped, and the fumes can be hazardous in the wrong places. Use them with the product label as your rulebook, and focus on sealed storage instead of open, occupied areas.

For more help, see our Mothball Placement: Legal Label Use and Safety Limits guide.

What mothballs are and how they work

Mothballs are pesticide products that release a vapor designed to protect stored items from certain fabric pests. Their effectiveness depends on keeping the chemical concentrated in an enclosed space, not spreading it around a home.

The chemistry behind the smell and vapor

Mothballs contain pesticides mixed into a solid that slowly changes into a gas (a vapor) over time. The strong odor you notice comes from that vapor as it escapes from the solid. In a sealed container, the vapor builds up to a level that deters or harms pests that target fabrics. In an open room, the vapor disperses fast, so there is not enough concentration for the product to work the way the label intends. That same vapor is also why safe handling matters, because it can irritate lungs and eyes and pose risk to people and pets.

Why they repel insects and rodents rather than kill them outright

Most mothball products are aimed at pests that live in stored goods, especially larvae that damage wool, fur, and other natural fibers. The vapor creates an environment pests avoid, and at sufficient concentration it can also harm them. Rodents are not the intended target the way fabric pests are, and mothballs are not a fast kill method. Think of mothballs as a chemical barrier in sealed storage, not as a whole-home extermination tool. If pests can enter, nest, and feed without the vapor staying concentrated around them, the mothballs will not solve the problem.

How long they slowly evaporate in enclosed spaces

The release rate depends on the product formulation and temperature, but the label determines the expected duration. In practice, mothballs work by gradual evaporation while they are confined. If you place mothballs in a sealed garment bag, airtight tote, or lidded storage bin, the vapor stays in contact with the stored items. If you place them in a loosely closed area, the vapor leaks out, the odor drops quickly, and the protection declines. Replace mothballs when the odor fades and the label indicates it is time, especially for seasonal storage.

Where mothballs may be used legally

Legal use depends on the exact product label for your mothball type (camphor, naphthalene, or other active ingredients) and the application conditions. Labels often restrict mothballs to sealed containers or specific storage setups.

Closets, garment storage, and sealed containers

Use mothballs only in the configurations the label allows. For stored clothing, pack items in a tightly closed garment bag or a sealed plastic tote with a lid. Add mothballs inside the container, not directly on shelves, floors, or near food. For closet use, follow label directions for where to place them and how many, then keep the storage sealed to prevent vapor from filling the rest of your home. Keep items that touch skin, like underwear and pajamas, protected by fabric barriers (bags or garment covers) so you do not transfer odor or residue.

Rules and risks for attics, crawl spaces, and other hidden areas

Attics and crawl spaces are not the safe storage solution people assume. Many labels restrict mothballs to enclosed storage spaces because ventilation and airflow can spread vapors into living areas. If an attic or crawl space has ducts, plumbing chases, or vents that connect to the indoors, vapor movement can expose occupants even if you did not place mothballs “in the room.” For hidden areas, the safest approach is to use pest control methods designed for those spaces, like sealed entry repair, insulation-safe treatments, or targeted traps. If you still want mothballs there, use only if the label explicitly authorizes that location and amount.

Why car engines, living rooms, and open rooms are usually the wrong place

Mothballs are not meant for cars, occupied rooms, or open areas where people breathe the vapor daily. In a living room or open closet, the vapor disperses, so you lose effectiveness while increasing exposure risk. In a car engine bay, heat can change the release rate and increase odor and irritation. Labels generally prohibit these uses, and violating label directions can be illegal and unsafe. If you are trying to solve a pest issue in an occupied space, use a legal method that targets the pest without filling the air with pesticide vapor.

How to use mothballs safely and effectively

Proper use is about controlling where the vapor goes and keeping exposure low. Follow the label exactly, because the “right amount” depends on product formulation and containment size.

Use only the labeled amount in a fully enclosed space

Read the product label for the exact number of mothballs per container size (for example, per cubic feet, per bin, or per garment bag).
Place mothballs inside a sealed container that you can close fully, such as a lidded storage tote, sealed plastic bin, or garment bag you can zip or tie tightly.

Keep mothballs off fabric and off surfaces that you will later store items on. Use the container as the barrier.
Close the container completely and leave it closed for the storage period. Ventilate only when it is time to use the items.

Keep them away from children, pets, food, and fabrics that touch skin

Keep mothballs in locked or high storage where children and pets cannot access them. Do not store them in a kitchen drawer, pantry, or near food packaging. For clothing, use mothball containers designed for storage so the vapor does not linger on items that touch skin. Keep mothballs away from towels, bedding, and any garment you will wear immediately after opening the container. If the label allows use near stored fabrics, still create separation through a sealed bag or an outer garment cover so you reduce odor transfer and direct contact.

Ventilate before reopening a treated space

Plan to open treated storage in a ventilated area, outdoors if possible, or in a space with strong airflow.
Open the container only after the mothballs have been in storage for the intended period.
Leave the container open briefly to vent the odor and vapor before you handle items closely.

Once ventilated, remove clothing and let it air out before wearing it, especially items that contact skin.

Do not run fans that blow vapor into occupied rooms. Ventilation is for your exposure control and odor reduction, not to spread pesticide throughout the home.

What mothballs can and cannot do

Mothballs are helpful for a specific job, protecting stored clothing from certain fabric pests. They are not a universal solution for household infestations.

What pests they may deter and what they will not solve

Mothballs are mainly intended to protect stored clothing from moth larvae and similar fabric pests that feed on natural fibers. They do not reliably address common home problems like cockroaches, ants, or active infestations where pests are living and breeding in walls, floors, or cabinets. If you already see droppings, egg cases, or live insects moving around, mothballs will not fix the root cause. They work only when the vapor stays concentrated where pests are expected to be accessing stored items.

Why they are a poor choice for rodents, termites, and active infestations

Rodents and termites are not controlled through a scent-based vapor barrier in the way mothballs are marketed for fabric storage. Rodents move, nest, and feed across different areas, and mothballs do not create a consistent lethal or repellent field. Termites live in structures and feed where you cannot easily reach with vapors, and controlling them requires inspection and targeted treatments. For active infestations, mothballs waste time and can delay proper treatment, while pests continue to damage property. Use baiting, traps, or professional treatments that match the pest and the environment.

Common myths about household deodorizing and pest control

A common myth is that mothballs “deodorize” a room. In reality, the odor is the chemical vapor itself, and the product is not meant to freshen living spaces. Another myth is that putting mothballs anywhere pests are a problem will stop them, but mothballs work only in the sealed, label-approved setups. Some people also assume odor equals success, but effectiveness depends on concentration, not just smell. If the odor drops because vapors escaped, the protection drops too.

Health, material, and environmental risks

Even when mothballs are used correctly for storage, you still need to understand exposure risks and potential damage to materials.

Effects of mothball fumes on people and pets

Mothball vapor can irritate the eyes, nose, and throat, and it can trigger breathing discomfort, especially in people with asthma or other respiratory issues. Pets are also at risk because they may investigate containers or be attracted to the odor. Ingestion or significant exposure can cause serious illness. For safety, store mothballs in labeled packaging inside sealed containers, keep them out of reach, and do not use them in occupied spaces. If exposure occurs, follow the product label instructions and contact a medical professional or poison control.

When mothballs can damage plastic, rubber, or metal surfaces

Some mothball chemicals can stain or discolor finished surfaces and can harm materials that absorb vapors. Plastic and rubber are the most sensitive, especially in tightly enclosed containers where vapor contacts the walls for long periods. Finished metal surfaces can also tarnish with prolonged exposure or improper storage. Prevent damage by keeping mothballs sealed inside the approved container and avoiding direct contact with surfaces that you want to keep in good condition. If you notice discoloration on a bin or bag, stop using that setup and switch to fresh, compatible storage.

Warning signs of overuse or unsafe exposure

Watch for strong, lingering odor in areas where it should not exist, like your closet after you opened it, or any room where you did not intend to release vapors. Another warning sign is visible irritation, coughing, or watery eyes among household members or pets after storage is accessed. Overuse can also cause residue or staining on items inside storage containers. If you smell mothballs in occupied spaces, ventilation is not the only concern, it means the vapor is escaping containment. Reduce exposure by tightening sealing and following the labeled amount and duration.

Disposal, cleanup, and safer alternatives

When you are done, disposal and cleanup matter. Old mothballs and contaminated packaging should be handled as hazardous waste if your local rules say so.

How to dispose of leftover mothballs and contaminated packaging

Check the product label first for disposal instructions, including whether the container is empty and safe to discard.

Do not burn mothballs, do not dump them outside, and do not pour remnants down drains.
Bag leftover mothballs and any heavily odor-impacted packaging materials in a sealed plastic bag.
Follow local hazardous waste guidance for drop-off locations and accepted pesticide products.

If you used mothballs in a container that smells strongly, follow local guidance for how to treat or dispose of that container, especially if it cannot be cleaned without residue.

What to do if mothballs were used in the wrong place

If mothballs were used in an open room, near food, in a car, or somewhere occupied, stop using them immediately. Remove mothballs only while people and pets are kept away, then ventilate the area according to safe handling guidance on the label. Seal any remaining mothballs in a closed bag or container to prevent ongoing vapor release. Dispose of them according to label and local hazardous-waste rules. Clean surfaces with the gentlest method that does not spread residue, then air the space until odor fades. If anyone had symptoms from exposure, contact poison control or a medical professional.

Lower-risk storage and pest-prevention alternatives

If your goal is stored clothing protection, use airtight storage containers for seasonal items. Vacuum-seal bags work for many fabrics and reduce pest access without chemical vapor. For existing pest problems, traps and targeted baits are better tools than mothballs. For fabric pests, wash and dry items before storage, and store clean clothing in sealed containers so moths cannot lay eggs on fibers. For rodents, seal entry points, remove food sources, and use snap traps or professional exclusion methods. Choose the approach that matches the pest and the location, so you avoid unnecessary pesticide exposure.

Frequently Asked Questions

How do mothballs work?

Mothballs release a pesticide vapor that builds up in sealed spaces and repels or harms certain fabric pests. They only work as intended when the vapor stays concentrated enough, which is why ventilation, open rooms, and most household uses are ineffective.

How many mothballs should I use in a room?

Generally, you should not use mothballs in a room unless the product label specifically allows that setup. They are meant for enclosed containers or tightly sealed storage, not occupied rooms, because the fumes can be unsafe.

Do mothballs corrode metal or damage surfaces?

They can damage or discolor some materials, especially plastics, rubber, and finished surfaces. Metal corrosion is not their main purpose, but poor storage or prolonged exposure can still cause problems, so keep them away from sensitive items.

What do mothballs get rid of?

They are mainly intended to protect stored clothing from moth larvae and similar fabric pests. They are not a reliable cure for rodents, cockroaches, termites, or a general household pest problem.

Are mothballs legal to use anywhere?

No. Their legal use is limited to the conditions on the product label. Using them outdoors, in living spaces, in cars, or for unapproved pest control can violate label directions and create health hazards.

How should mothballs be disposed of?

Follow the product label and local hazardous-waste rules. Do not burn them, dump them outside, or throw large amounts into regular trash if local guidance says otherwise.