By Chris Williams on January 2, 2018.

Hello. I have a question about clothes moths. At the end of the winter, I’ve always stored my wool clothes in boxes to which I add some moth balls. This year when I took my clothes out of the boxes, I found some holes in my sweaters. My aunt says that moth balls don’t really work to kill clothes moths. Is that true? C. Y., Rochester, NH

I’m afraid that is true, for the most part. While we didn’t really expect mothballs, moth crystals, or moth cakes to kill clothes moths, most of us assumed that they were at least repelling the moths, keeping them away from our woolens. Research has shown that these moth protectants containing naphthalene or paradichlorobenzene don’t even do a very good job of repelling clothes moths. In a laboratory setting, these products might work to some extent, but in the real world they are almost never used in sufficient amounts or in true air-tight situations.


Most people don’t know that mothballs and moth crystals are registered pesticides and that misusing them is a violation of federal law (see Mothballs Are Pesticides and Require Precautions). These products are fumigants, pesticides that work by producing a toxic gas. If you don’t use enough moth balls or if the resulting fumes escape the container, you won’t get a high enough concentration and it’s not going to work. For the record, cedar chests and cedar-lined closets don’t work very well against clothes moths either, and for the same reasons.


Experts say that instead of spending your money on mothballs, you should spend it at the dry cleaners and on air-tight storage boxes. Cleaning your clothes before you store them away is very important since fabric pests (including carpet beetles and silverfish) prefer to feed on items that are soiled, even with just perspiration (see Why Do Fabric Pests Prefer to Dine on Dirty Clothes?)

You said that you store your woolens in boxes. If you mean cardboard boxes, your clothes don’t stand much of a chance against fabric pests, even with sufficient mothballs. Store your clean woolens in plastic boxes or zip bags that have an air-tight seal. Even some of the newer plastic storage bins with snap-on lids have gaps that would allow insects inside and gases out. A Tupperware-type lid is better.

If you’re having a problem with clothes moths or other fabric pests in clothes, rugs, blankets, even trophy heads, give Colonial Pest a call for a professional inspection and premises treatment. For more on how to protect your woolens from clothes moths, see these Colonial blogs:

You Found Moths in Your Winter Clothes, Now What?
Tips to Protect Your Woolens From Clothes Moths



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