How to safely bring new-to-you yarn or knitwear into your collection
Moths can be beautiful but clothes moths are not what a wool lover wants to see. Here’s how to make sure your knitwear and yarn are safe.
Not too long ago, a friend of mine suffered through a bout of carpet beetles in her home and traced the problem to a piece of thrifted knitwear.
Just writing the word “carpet beetle” gives me the heebie-jeebies and reminds of when my now teenaged kid was a preschooler. I lived in fear of getting a notice of a lice outbreak at school.
I quickly learned, however, that kids and lice do not equal a dirty or unsanitary home. It's just one of those unfortunate parts of being human. Sometimes, it happens, and so you should simply know how to deal with it or prevent it, as best you can.
Similarly, knitwear and clothes moths, carpet beetles or other little creatures that like to eat wool are a fact of knitting life. Having clothes moths (or carpet beetles) does not equal a dirty or unsanitary home. Sometimes it simply happens.
When I first had the idea for the Swap Shop—a new offering for paid newsletter members that rolled out on Sunday—I kept thinking about how to ensure that the knitwear we would swap would not endanger anyone’s knitwear or stash.
I found some solid, well-researched answers for you.
Proactively treat new-to-you yarn and knitwear as if has a wool-eating critter you can’t see
Whenever you bring knitwear or yarn into your home, whether it's from a thrift shop, resale shop, destash, or our very own Swap Shop, you should ensure—with 100% certainty—that it is free of clothes moth or other eggs so tiny you can’t even seen them.
There are lots of articles around the Internet with lots of different approaches on how to do this. Most of the colloquial information explains how to deal with a carpet beetle or clothes moth infestation once you’ve noticed damage. I found lots of advice, without sources, to do things like rotate your yarn in and out of your home freezer to putting yarn in plastic bags and letting it sit outdoors in the sun.
I set out to find out actual advice from textile conservators about how to proactively protect your wool, not just colloquial advice about what to do if you notice damage.
In the research process, I learned something really interesting: most colloquial advice doesn’t do much to actually protect your wool or treat an infestation.
Lavender sachets and cedar cubes are mostly ineffective at repelling pests. Most home freezers don’t have a low enough temperature to kill eggs. And, visual inspections of yarn or knitwear isn’t helpful either. Carpet beetle or moth eggs are so small we usually can’t see them. We only find evidence of their damage.
I also learned that all eggs (whether carpet beetle or clothes moth or other wool-eating pest) are destroyed at a temperature of 120 degrees.
You know what I do at temperatures that high, and higher?
Dye yarn. Wool, even non-superwash wool, can be safely heated at home, in water, at a temperature higher than 120°F (49°C) and yet still less than boiling at 212°F (100°C). Which leads me to recommend the following:
A dyer’s guide to doing a safe, at-home hot water treatment to proactively remove any potential wool-eating critters
Fill a very large pot with cool water (it can be a pot also used for cooking, since you will not be adding dyes or anything other than wool and water to this pot).
Submerge the knitted item in the pot.
Leave it for at least 20-30 minutes until the item is thoroughly soaked.
Slowly heat the water and knitwear (I like to use a medium heat), gradually increasing the temperature until it reaches a temperature higher than 120°F (49°C). You can use a candy thermometer, but here’s an easier way: When you start to see steam wafting across the top of the water, but it has not reached a boil, this temperature is between 160° and 185°F (71° to 82° C)
Leave it at this steamy-not-boiling temperature for a few minutes. Do not stir or agitate.
Turn heat off and let water and knitwear cool until it is room temperature. (I let things cool overnight.)
Drain water, wash your pot, and block the knitted item as usual.
This temperature of water (~185°F or 82°C) will kill any larvae of clothes moths or carpet beetles or any other pest that can damage clothing—even eggs that are too small to see—and this temperature of water will not damage wool. It's the same temperature at which I dye yarn. Just be sure not to boil and not to agitate, and the wool will not felt.
You can also take your item to a dry cleaner, but save yourself the money and save the environment the chemicals and do this simple at-home hot water treatment instead.
If you do a hot water treatment of any new-to-you yarn or knitwear you bring into your house, you can be assured that it will not introduce unwanted wool-eaters into your larger stash or knitwear wardrobe.
Bookmark this newsletter and come back to it the next time you add a piece of thrifted knitwear to your collection or the next time you purchase yarn from a destash.
Sources:
I found this NYT Wirecutter article to be extremely helpful and it has citations from the Smithsonian Museum Conservation Institute, Cornell University and the Fashion Institute of Technology. (paywall $)
This interview with a textile conservator is also helpful.
Here’s a reminder that the Swap Shop is in full swing, and paid members of this newsletter community have first dibs for another week on claiming any item of knitwear that you want. It’s all free, and you only pay for shipping. There are still 6 sweaters available (all are smallish, or around 34-36 inch bust size, a gorgeous silk and wool cowl, a stunning wool hat, and a wool/cashmere shawl knit by yours truly). I’ll put the link below, behind a paywall.
If funds are tight, you can request a one-year (free to you) community-supported membership here. No questions asked. If what I’m doing, and how we are building community, feels like your people? We got you.
(If you are a new paid subscriber, read this locked post, once you’ve subscribed, for the Swap Shop link.)