Written by: Allison Beach, BCE-Intern for Franklin Pest Solutions

Mothballs have been used for decades as a quick fix for insect problems, especially when it comes to protecting stored clothing. But do mothballs actually work to keep bugs out of the house, or has their effectiveness been overstated over time?

Do Mothballs Actually Work to Keep Bugs Out of the House?

The answer is more nuanced than many homeowners realize. Understanding what mothballs are designed to do, how they work, and the risks associated with improper use can help you decide whether they are appropriate for your home.

Mothball FAQs

Q: What Are Mothballs, Really?

A: Mothballs are pesticides that come in solid form and are commonly made from one of two chemicals: naphthalene or paradichlorobenzene. These chemicals slowly change from a solid into a gas through a process known as sublimation.

The strong odor most people associate with mothballs is actually chemical vapor being released into the surrounding air. Under the right conditions, that vapor can kill certain insects. However, those conditions are very specific and limited.

Q: Why Don’t Mothballs Keep Most Bugs Out of the House?

A: Mothballs only work under very specific conditions and against a limited group of insects.

They are regulated pesticides with clearly labeled directions for use. According to those labels, mothballs are intended to control fiber-feeding pests, such as clothes moths and related insects that damage fabrics.

When used properly inside sealed garment bags or airtight storage containers, mothballs can help protect stored clothing. In open areas like closets, basements, attics, or garages, mothballs cannot maintain a strong enough concentration of vapor to be effective.

This means mothballs do not work to keep bugs out of the house in general living spaces. They do not repel ants, spiders, cockroaches, mice, stink bugs, or other common household pests. Using mothballs outside of their labeled purpose is not only ineffective, it can also be unsafe.

The Hidden Risks of Using Mothballs

Many homeowners are surprised to learn that mothballs are regulated pesticides, not household deodorizers or repellents. When used improperly, they can expose people and pets to harmful chemicals.

Potential risks include:

• Toxic fumes that may cause headaches, dizziness, nausea, or respiratory irritation. If you can smell mothballs, you are being exposed to their vapors.

• Increased risk for children and pets, as mothballs can sometimes be brightly colored and mistaken for candy or toys.

• Improper use in open spaces or outdoor areas, where mothballs are not labeled for use.

Using mothballs outside of sealed containers increases exposure risk without providing effective pest control.

Q: Are Mothballs okay to Use As A Long-Term Pest Solution?

A: Even when used correctly for fabric protection, mothballs do not address the underlying reasons pests enter a home. 

Insects typically invade because of food sources, moisture issues, or access points in the structure. Relying on mothballs may temporarily hide a problem while allowing infestations to continue unnoticed. For example, clothing moths often indicate improper storage or existing fabric damage, while other household pests may signal sanitation or structural concerns that need attention. Franklin Pest Solutions offers free pest inspections focused on identifying the source of pest activity, which is key to long-term prevention.

Safer Alternatives to Mothballs

If your goal is to protect clothing from clothes moths or prevent fabric pests, consider these safer options:

• Wash or dry clean clothing before storage

• Store items in airtight containers or vacuum sealed bags

• Keep storage areas clean, dry, and well organized

For general household pest prevention:

• Seal cracks and gaps around doors, windows, and foundations

• Reduce clutter that provides hiding places for insects

• Address moisture issues, especially in basements and crawlspaces

These steps help keep pests out of the house without introducing unnecessary chemical exposure.

Q: When Is It Time to Call a Professional?

A: If you are seeing repeated pest activity or are unsure what type of insect you are dealing with, professional pest control is the safest way to get answers. A trained service professional can correctly identify the pest, recommend targeted treatment, and provide prevention strategies specific to your home.

The Bottom Line

So, do mothballs actually work to keep bugs out of the house? Only in very limited, tightly controlled situations involving fabric pests. They are not an effective solution for general household pest control and can pose health risks when misused.

Long-term pest control starts with understanding why pests are present and addressing the conditions that attract them.