Can Yarn Go in the Microwave? (4 Microwave Safe Project Ideas)

From dyeing yarn to rice-packed heating pads, there are a ton of reasons why you might wonder if yarn can go in the microwave.

Yarn can go in the microwave, but only natural fibers. You should never put any synthetic fibers in the microwave, they will melt. Natural fibers include but are not limited to wool, cotton, silk, and linen. Synthetic fibers include acrylic, nylon, polyester, and viscose. 

We’ll get a little more specific about which yarns and fibers can go in the microwave and why you might want them to. 

Table of Contents

Can Yarn Go in the Microwave?

can yarn go in the microwave

Let’s break all the types of yarn into two major types; natural fibers and synthetic fibers. We’ll discuss each type and whether it can go in the microwave.

Natural fibers

Natural fibers are things that are, well, natural. They come from animals, plants, and insects (in the case of silk). All-natural fibers and blends of natural fibers are microwave safe.

Below is a list of natural fibers that are microwave-safe:

  • Wool
  • Alpaca
  • Camel
  • Yak
  • Qiviut
  • Mink
  • Cashmere
  • Angora
  • Llama
  • Mohair
  • Silk
  • Cotton
  • Linen (Flax)
  • Hemp
  • Bamboo
  • Tencel
  • Banana
  • Ramie
  • Pineapple

I tried to be as thorough as possible with this list but I could be missing things. But, if the fiber content of your yarn comes from plants or animals then you’re probably good to put it in the microwave.

Synthetic Fibers

Synthetic fibers are incredibly common in big-name yarn stores such as Hobby Lobby, JoAnn’s Fabrics, and Michaels. It’s getting harder and harder to find yarns at these stores that don’t have some kind of synthetic fiber blended in. 

All synthetic fibers will melt, catch on fire, or both when they’re heated in the microwave. For that reason, you should never put synthetic fibers in the microwave. 

Unfortunately, that means that if your yarn has a synthetic fiber blended in, you can’t put it in the microwave either. 

Below is a list of synthetic fibers that you should NOT put in the microwave:

  • Acrylic
  • Nylon
  • Polyester
  • Rayon
  • Viscose
  • Lyocell
  • Spandex
  • Polypropylene
  • Kevlar

If your yarn label has any of those fibers listed, then don’t put your yarn in the microwave. If you’re unsure about something that’s listed on your label, do a quick google search for it; if it’s from a plant or animal, you’re good to go, if not, better play it safe and not stick it in the microwave. 

Why Put Yarn in the Microwave?

Well now that you know if your yarn can go in the microwave, you might also wonder why you may want to put yarn in the microwave. 

There are a couple of different reasons, let’s jump in!

Heating Pads

You probably know what I’m talking about, but something that a lot of people make with yarn or sew with fabric are heating pads. 

What you do is make a little pouch, fill it with rice, then seal your pouch. When the rice is heated in the pouch in the microwave, it creates a nice little heating pad that holds the heat for quite a while. 

The rice also conforms to your body which makes it great for soothing awkwardly shaped body parts like your knees. 

Bowl Cozies

Another thing people create with the microwave in mind are bowl cozies. 

I have a few bowl cozies made out of microwave-safe material that a friend of mine made for me. These guys are great if you like your food extremely hot like I do. You just put your bowl in the cozie before you stick it in the microwave, then, when you take it out, you don’t burn your hands on the piping hot bowl. 

Hot pads

This one’s a little tricky, you can make hot pads out of yarn, but, I don’t recommend making it out of wool or animal fibers. While these fibers are microwave safe, they melt or smolder when exposed to direct flame or extreme heat. 

For that reason, you really only want to make hot pads out of cotton, just to be safe. 

That being said, hot pads are a quick easy project and a great gift. Here’s a link to a great knit potholder pattern.


The next reason you may want to put your yarn in the microwave is to dye it fun colors. 

You’re probably thinking I’m crazy right now, but seriously, you can dye your yarn in the microwave!

All you have to do is soak your yarn in either plain water (for plant fibers) or a mix of water and vinegar (for animal fibers). Now get a microwave-safe dish and put your yarn inside

You can either microwave your yarn in this microwave dish with a lid on top, or you can wrap it in plastic wrap and put it in the dish. This traps the steam inside which sets the dye. 

Don’t ring out your yarn! You need some liquid in the yarn to make sure it doesn’t heat unevenly and cause the yarn to get scorched. But, you also don’t want too much liquid or else your dyes will bleed into one another (unless you want them too). 

A good rule of thumb is to not have standing water on top of the yarn, but if you push the yarn down with your fingers, there’s water. 

Now the fun part. Apply your desired color of dyes, you can dye it a single color or do something called ‘hand-painting’ and put different colors along your yarn. The type of dye you’ll use will depend on the type of yarn/fiber you are dyeing. 

After your colors are the way you want them, pop your dish and yarn in the microwave. 

Microwave the yarn for a few minutes at a time, check it in between to see if it’s done. 

How do you know if it’s done, you ask? Once the water in your dish is clear, your dye is set. 

Take your dish out of the microwave. I recommend letting the dish and yarn cool off for a couple of hours before you wash it. This helps ensure that all the dye gets absorbed properly. 

Once you’re ready, wash your yarn, being especially careful of felting while you wash it.  

And done! You dyed some yarn! You can also do this same process with fabric and spinning fiber. 

If you need a visual of how this is done, here’s a video that shows the plastic wrap method I mentioned earlier. 

Wrap up

You may have gotten a little more information than you were expecting when you first started looking to see if your yarn is microwave safe. But it’s all good information! Let’s review to make sure you got it all.

Animal and plant fibers make yarns that are microwave safe.

If your yarn is made of or blended with synthetic fibers, it will melt or even catch on fire in the microwave. 

If you have microwave-safe fiber, you can make heating pads, bowl cozies, and even dye your yarn in the microwave. 

With this new information in hand, go make something awesome!

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