The most effective replacement for mothballs is airtight storage, because a sealed bin is a physical barrier that never fades. For everyday closet use, cedar and botanical sachets are the practical choice: they deter adult moths from laying eggs and they leave clothes smelling clean. Nothing on this list matches the vapor of a mothball in a sealed container, but almost nobody uses mothballs that way anyway.
Start with the honest part. Mothballs work. People replacing them are usually not doing it because they failed.
They are replacing them because of the smell, because the container instructions are impractical, or because they inherited a wool coat that still smells like their grandmother's attic four years later. Those are good enough reasons. But knowing what mothballs actually do makes it much easier to pick something that fills the same job.
What mothballs actually are
Mothballs are solid naphthalene or paradichlorobenzene, both registered pesticides regulated by the US Environmental Protection Agency. They work by sublimating, passing from solid straight to vapor, and that vapor kills clothes moths at all life stages in an enclosed space.
Two details explain nearly every complaint about them.
They need a sealed container. EPA labeling directs that mothballs be used inside airtight containers, because the vapor has to reach and hold a certain concentration to do anything. In an open closet the vapor disperses, the concentration never gets there, and the result is a closet that smells strongly while offering fairly little protection. Most people use them in exactly this way.
The smell binds to fabric. Naphthalene vapor is absorbed by fibers, particularly wool, and releases slowly for a long time afterward. This is why airing a garment for a week often does not clear it.
So the realistic comparison is not "mothballs versus sachets." It is "mothballs used correctly in a sealed bin versus everything else." Used incorrectly in an open closet, which is the norm, mothballs are not the high bar they are assumed to be.
What actually replaces them
1. Airtight storage
The most effective and least interesting answer.
A sealed bin with a gasket lid, or a vacuum bag, is a physical barrier. Adult moths cannot reach the fabric to lay eggs, and a barrier does not off-gas, fade or need replacing. For seasonal storage of wool and knitwear this outperforms every scented product, and it costs nothing after the initial bins.
The requirement is that clothes go in clean. Sealing a bin with larvae already in it protects them beautifully.
For long storage of natural fibers, leave a little air rather than going fully vacuum-sealed, since trapped humidity brings its own problems.
Best for: seasonal storage, anything you will not touch for months.
2. Cedar
The traditional answer, and a real effect, though narrower than the marketing suggests.
Aromatic eastern red cedar contains cedrol and thujopsene. Laboratory work has shown these can kill young clothes moth larvae at sufficient concentration. In a ventilated closet that concentration is rarely reached, and the oils off-gas over time, so the practical benefit is deterring adult moths from settling and laying eggs.
That is genuinely useful prevention, and it is not a rescue. Cedar will not clear a closet that already has larvae in it. Anyone telling you otherwise is selling something.
Cedar also needs maintaining. Blocks need light sanding every few months to reopen the pores. Sachets and hanging tags get replaced instead, which most people find easier to actually keep up with. Our Bloc Off sachets are built on that replacement cycle.
Best for: everyday closet and drawer protection in a closet that is already clean.
3. Botanical sachets
Lavender, rosemary, thyme, cloves, mint and similar aromatics are disliked by adult clothes moths. The effect is modest and the scent is the main draw for most buyers, which is a perfectly reasonable thing to want.
Treat these as a deterrent layer and a fragrance, not as protection on their own. They pair well with cedar, which is why most sachets combine them.
Best for: scent plus a light deterrent layer, in drawers and hanging space.
4. Cold and heat
Not a storage product, but the most reliable way to kill what is already present.
Freezing at 0°F for at least 72 hours kills eggs and larvae, and a second cycle after a few days at room temperature improves the odds. Washing at 120°F or above does the same, where the care label allows it. Dry cleaning kills all life stages.
Best for: treating items before storage, not for ongoing protection.
5. Pheromone traps
These attract and catch adult males using a synthetic pheromone lure.
They are best understood as monitoring. They tell you whether you still have a population and roughly where it is concentrated. They will not clear an infestation, because catching some males does not stop the females already laying.
Useful diagnostically, especially after a cleanout, to confirm the problem is actually over.
Best for: checking whether you still have a problem.
What to skip
Essential oil sprays as primary protection. Cedarwood or lavender oil sprayed on fabric evaporates within days, can stain, and does not build the sustained presence that matters. The oil is doing real work in a sachet precisely because the release is slow.
Scented drawer liners. Pleasant, brief, and no meaningful deterrent effect beyond the first couple of weeks.
Ultrasonic pest repellers. There is no good evidence these affect clothes moths. The US Federal Trade Commission has previously taken action against unsupported claims for ultrasonic pest devices generally.
Cedar that no longer smells. An old cedar chest or a block that has gone quiet is decorative. The scent is the mechanism, so no scent means no mechanism.
Anything sold as a permanent solution. Every option here is either a barrier you maintain or a scent you replace.
Picking by situation
| Situation | Use |
|---|---|
| Storing wool for the season | Clean, then airtight bin. Add a block inside |
| Everyday closet, clothes in rotation | Hanging cedar sachets, spaced along the rod |
| Dresser drawers | One block or sachet per drawer |
| One valuable coat or suit | Cedar ring on that hanger, sachet in the closet |
| You already have holes | Stop and read the full cleanout guide first |
| Closet smells musty, no holes | That is moisture, not moths |
If you want the format comparison in more depth, we broke it down in cedar sachets vs rings vs hangers.
The short version
Mothballs work, but they need a sealed container to do it and the smell stays in wool for years. The honest replacement is not one product, it is two habits: store clean clothes in something sealed, and keep cedar in the closet you use daily.
Neither is dramatic. Together they are more effective than a jar of mothballs sitting in an open closet, which is how most of them get used.
Our moth repellent sachets and cedar blocks cover the everyday half of that.
By Tanya Lee, Co-Founder of The Superbloc.
Sources: US Environmental Protection Agency on mothball registration and labeling requirements; US Federal Trade Commission actions regarding ultrasonic pest device claims; university extension entomology guidance on clothes moth management; published laboratory work on cedarwood oil constituents.