Instagram iconInstagram icon
Facebook iconFacebook icon
pinterest iconpinterest icon
YouTube iconYouTube icon
Tiktok iconTiktok icon
LTK iconLTK icon

Make Your Own Laundry Soap (Using the Microwave Method!)

Six years ago, we decided to try our hand at making our own laundry detergent. It started as an experiment in saving some money, but then something happened – we never stopped. It’s cost effective and we like that this mixture leaves our clothes clean without the heavy scent of ‘mountains’ or ‘fields of flowers,’ but most importantly, it works! The lack of perfumes and dyes is friendly for the allergy prone (aka, us and every single animal that lives in this house!), and we’ve used it in both a standard washer and, most recently, our H/E machine, too.

There are just 3 ingredients to the recipe – borax, washing soda and a bar of Fels Naptha soap – and all of these items can usually be found in the grocery store, in the same aisle where you’d buy the big name detergent brands (often times, you’ll find them tucked on the lowest shelf). The longest part of the process has always been grating the bar of soap to make the dry mix, but many of you recommended the microwave method, claiming that it saves your arms a workout. (I’ll take that!) A few months ago, I tried this new-to-me method for the first time and shared the process in an Instagram Story, and we received so many questions, I thought I’d share over here just how easy it is to replicate.

I always make a double batch at once, but whether you’re making two batches or five, the math is simple: 1 bar of Fels Naptha + 1 cup borax + 1 cup washing soda = DIY laundry detergent. In the past, I used a cheese grater to whittle down my soap, but the microwave method nixes that step altogether!

Here’s How:

Cut up the bars into thirds or fourths, and put them on a microwave safe plate. Microwave for 2-3 minutes, and allow them to cool for up to one hour in the microwave. It’s so important to leave them be, because not only will the soap be extremely hot, but the strong smell of Fels Naptha will dissipate the longer it’s left untouched.

In the meantime, mix equal parts borax and washing soda in a large bowl. If you used a single bar of soap, you’ll use 1 cup of each. If you used two bars of soap, you’ll use 2 cups of each – and so on.

Once the soap has cooled, take it out of the microwave. Each chunk should have ballooned into twice its original size. (It’s weirdly magical. Science!) Toss them into a quart bag, and pound with a fist. The soap will easily crumble into a fine powder, and it can then be whisked together with the borax and washing soda mix:

That’s it!

Our double batch fits perfectly in one of these glass jars (we use these jars for everything from stashing coffee to cat food!), and we keep this 2 tablespoon scoop inside.

Only 1 tablespoon is needed for a regular load, but toss in a small amount more for larger loads. We currently have a H/E washing machine, and we’ve had great success putting the soap mix right into the detergent tray, although others swear by adding the detergent right into the drum along with the clothes. Tip: Resist the urge to use more than you need, as too much can dull your clothes! 

Since completing the laundry room renovation, we also keep a wedge of Fels out by the sink. It has been an absolute miracle as a stain pre-treater; simply run it under water and rub it into anything stubborn. Before washing any of our dog bed covers, I’ll take a moment to pre-treat the worn down areas, and they always come out of the wash looking great.

Some of our readers have swapped in Kirk’s Castile, Zote or Ivory in place of the Fels Naptha, and we’ve even heard of using OxiClean as an additional whitening boost! For anyone who may be having trouble finding the ingredients at your local grocer, you can get a starter pack right here. One box of both borax and washing soda will yield you many, many batches of detergent (we only buy these two ingredients maybe once a year), so we’re always sure to stock up on bars of the Fels Naptha soap.

Happy washing!

Add a comment...

Your email is never published or shared. Required fields are marked *

  • Rebekah Martin2.28.17 - 7:20 AM

    This is great info to have. I HATE having to grate the soap! It takes so much time!ReplyCancel

    • Moxie2.28.17 - 9:56 AM

      Before we switched to the microwave method, we used the fine grater disc and our food processor. You have to rinse it pretty thoroughly before using it for food, but it’s not that bad.ReplyCancel

    • Kathy3.1.17 - 9:04 AM

      Another great tip for grating soap is to use one of those rotary cheese graters with a handle, or if you’re lucky to find a Salad Shooter (remember those?) at a thrift store, use that!ReplyCancel

  • Cara2.28.17 - 8:30 AM

    Can’t wait to try this. I love that it’s natural and cheap:) My two favorite things!! Thanks for the info.ReplyCancel

  • Sarah2.28.17 - 8:47 AM

    Dying to try this! It looks so simple and bonus of it looking pretty in the glass jar. :)ReplyCancel

    • Kim2.28.17 - 9:23 AM

      So much prettier than a bright orange jug :)ReplyCancel

  • Kate2.28.17 - 9:05 AM

    I double the batch and use one bar of Fels Naptha and one bar of Dr. Bronners Eucalyptus. We don’t have sensitive skin in this house so it makes it smell even better without being to Mountain Fresh. I’ve been cutting the soap into smaller chunks in pulsing in our food processor which works great!ReplyCancel

    • Kim2.28.17 - 9:21 AM

      Ooh, love that idea! Thanks, Kate!ReplyCancel

      • Kate2.28.17 - 9:24 AM

        I should have proofread my comment. *too mountain fresh *and pulsing.

        So embarrassed ?ReplyCancel

        • Kim2.28.17 - 2:34 PM

          The grammar police are going to let this one slide, don’t you worry.ReplyCancel

    • William1.27.24 - 1:41 PM

      Any problems with a Septic System?  Z Guy, Warrendale. PAReplyCancel

  • Kate2.28.17 - 9:29 AM

    In a separate jar, mix a cup of salt (regular salt works, but Epsom does too – if you have hard water, stick to regular) and 20-30 drops of essential oils, toss in the drum of the washer before adding your clothes and you have a natural fabric softener, too!ReplyCancel

    • Kate2.28.17 - 9:30 AM

      Forgot to add – if you try this, you’ll want to add vinegar in the bleach compartment for a rinse.ReplyCancel

      • Kim2.28.17 - 12:24 PM

        Great tip! We already use white vinegar in the bleach compartment, but haven’t tried essential oils. Maybe that’s our next experiment!ReplyCancel

    • Laura C3.3.17 - 8:06 AM

      Do you put the entire cup of salt in for each load, or some smaller quantity? Thanks.ReplyCancel

      • Kim3.3.17 - 2:13 PM

        I’m not sure what you mean by salt? This recipe doesn’t call for any salt…ReplyCancel

        • Laura C3.6.17 - 8:19 AM

          Sorry – question was directed at Kate’s comment. Her essential oils idea is to mix them with a cup of salt.ReplyCancel

  • Sarah2.28.17 - 9:34 AM

    I used to make my own laundry detergent… for a year or two. But then my sister sent me this and I ended up switching to a plant based laundry detergent from Young Living.

    • Kate2.28.17 - 10:23 AM

      I second this. Good information. The Think Dirty app is a great tool if you’re looking to reduce unnecessary chemicals in your home.ReplyCancel

  • Josh @ The Kentucky Gent2.28.17 - 9:50 AM

    I’m going to save this for later! The idea of making this myself sounds genius, especially for a sensitive skin person like myself.ReplyCancel

  • Julie2.28.17 - 12:45 PM

    Hi, I live in Florida and spices, etc. get hardened because of the high humidity. Also, I have Oxi Clean powder that is hard as a rock. I have to use an ice pick to get small chunks off for the laundry. I’m guessing this mixture will harden up as well – thoughts?ReplyCancel

    • Kim2.28.17 - 12:52 PM

      Huh. I’ve never heard of that, but I can see how that can be the case. Can anyone from humid climates chime in?ReplyCancel

      • Henna3.1.17 - 12:36 PM

        Another Floridian here. As long as you keep the laundry soap in a closed container(same goes for the oxiclean) you shouldn’t have any issues.ReplyCancel

    • Sarah3.4.17 - 6:32 AM

      I’m from deep south GA and I never had problems with mine DIY laundry soap hardening up. If you have a good airtight container it shouldn’t be a problem.ReplyCancel

  • Megan2.28.17 - 1:15 PM

    Yes! I’ve been using this same recipe for a long time too, but was so happy to see your Instastory awhile back with the microwave tip. It has made the process so much better, and I feel like the ingredients mix better too, now I don’t have big sections of my container of just the Felz.ReplyCancel

    • Kim2.28.17 - 1:29 PM

      Right?! Microwaving has changed everything.ReplyCancel

  • Susan2.28.17 - 7:32 PM

    It is usually the scent of detergent that bothers me. Is the soap scented. I use dye/scent free detergent, but it is definitely not chemical free. Also, is the vinegar a necessary part of the process or a choice for additional cleaning/softening power?ReplyCancel

    • Kim3.1.17 - 8:04 AM

      The soap has a very mild scent, although it’s pretty strong once microwaved (which is why I strongly recommend allowing it to cool for an hour). However, the clothes have little to no scent once washed and pulled from the dryer!ReplyCancel

      • Kim3.1.17 - 8:05 AM

        Meant to add: vinegar isn’t a necessary step! It’s an option for a little brightening and softening.ReplyCancel

        • Katie3.1.17 - 10:08 AM

          Hello! I am so excited to try this. Can you please tell me about your vinegar use?, i.e., how much do you use and what do you think the benefits are? Thank you so much! I have never heard of making your own detergent before.ReplyCancel

          • Kim3.1.17 - 10:17 AM

            We use maybe a half cup (or whatever the ‘max’ line is), and we pour it right into the bleach tray. People use it as a softener, although we’ve always thought that it helps to brighten white!

  • Kelly3.1.17 - 2:34 AM

    I noticed that you have wool dryer balls. Do you use dark ones with your dark clothes or have you noted any shedding of “whie fiber” when using the light colored ones in your darker loads?ReplyCancel

    • Kim3.1.17 - 8:06 AM

      We use these with whites and darks! The dryer balls don’t shed onto dark clothing whatsoever.ReplyCancel

  • Life On Hill Street3.1.17 - 3:29 PM

    OMG whaaaat?! I had no idea that making your own laundry detergent was really a thing. Once we get back to our house (the contractors kicked us out, sad face) I’m TOTALLY doing this! I am so over my clothes smelling like a tropical flower explosion! Thanks for sharing, I’ve bookmarked this post :)

  • Charlotte3.2.17 - 6:34 AM

    It just occurred to me that I’ve been following your wonderful blog for 6 years! The original laundry soap post was the first thing I ever found on pinterest and it led me here to you! It’s hard to fathom all of the changes that have happened during those years but I’ll always be an avid follower, so thank you for letting us be apart of your journey! Much love to you all :)ReplyCancel

    • Kim3.2.17 - 9:16 AM

      Aw, thank you for following along all these years, Charlotte!ReplyCancel

  • Deanna3.2.17 - 11:19 AM

    I LOVE THIS POST! I have used this laundry soap recipe for years and love it so much…. except for the grating of the soap. I need to make a new batch soon, so I will be trying this method!! thank you for rescuing my arm from the tireless grating!!!ReplyCancel

  • So, I’m not sure I have the patience to make my own laundry soap, but, I sure do wish I had your laundry room! Haha, I love the wallpaper! An ostrich with its head in the sand? So cute!ReplyCancel

  • […] you tried making any of your own cleaning supplies before?  I’d really like to try this laundry detergent DIY from Yellow Brick Home…it seems pretty […]ReplyCancel

  • Happy Weekend, - 7:44 AM

    […] —Washing up: “It started as an experiment in saving some money, but then something happened – we never stopped.” […]ReplyCancel

  • Annabelle Kertscher4.9.20 - 11:22 AM

    An old meat grinder works wonders. However the microwave method sounds like an easier alternative. Thank you for postingReplyCancel

  • Mrs2.23.21 - 4:40 AM

    What are the little brown beads in the glass jar on your laundry table? ReplyCancel

  • Tessa8.11.21 - 2:09 PM

    Can somebody who’s actually tried it tell me if the microwave method works for Kirk’s soap? I tied it once and ended up with a pile of burnt soap that I had to throw out. But I struggle to get it grated fine enough in the food processor so I’d really like to get the microwave method to work. Not sure I cut it into chunks that time so maybe that was my mistake (it’s been a while so I don’t remember). Anyhow, would love to hear from a “soap veteran.” ☺️ReplyCancel

  • Kim7.1.22 - 2:20 PM

    I use oxi clean, super washing soda, baking soda, borax, fels naphtha and then add scent beads from Snuggle. Smells and works great.ReplyCancel

  • Teresa9.19.22 - 9:02 AM

    I make this soap but I find on delicate loads in cold water it doesn’t dissolve completely.  It leaves a residue on some items.  So I only use it on loads that are not set on delicate/cold.   I also take an extra step to make sure the fels naphtha has no chunks left – I use a food processor or hand blender for that.   Has anyone else had an issue with a residue left on clothes?   Any solutions?   I would like to use this exclusively but that issue stops me.  ReplyCancel

  • Anne2.23.23 - 8:27 AM

    I made this using my kitchen microwave and the soap smell lingered in the microwave for months.  No matter what I tried, I couldn’t get the soap odor out.  I found, on Facebook Marketplace, a used microwave near me for $10.  I bought it and put it in the garage just for “blowing up” my Fels Naptha! ReplyCancel

    • Nicole9.23.23 - 10:34 PM

      Hello Anne, I put a cup with vinegar in the microwave after I microwave the soap and it removes the soap smell. Hope this helps.ReplyCancel

      • Kathy10.2.23 - 1:21 PM

        Do you heat the vinegar or just leave the cup of it in there? ReplyCancel

  • allison10.25.23 - 11:39 AM

    For anyone wondering- this was a bit trickier using Zote soap. I’ve had trouble getting the Zote to dissolve in the wash and was hoping this could help me get a finer grain on it. I chopped up the zote before microwaving but only the outer parts would get to the crumbly texture later, so most of the it still had to be grated manually :/ In the future I’ll avoid using Zote for detergent either way.ReplyCancel

    • Katt2.6.24 - 1:41 AM

      Agree entirely. I didn’t microwave, just a *probably too thick* grate, it didn’t seem to do nearly as well as fels naptha. I’ve never had a problem with FN in cold water washes but I do put it in the drum vs. my tray ReplyCancel

  • Mose12.26.23 - 1:58 PM

    Excited to try this detergent! Was very easy to make but next time I will not be microwaving the fels. Even with the microwave closed the fumes stung my skin and eyes and the smell permeated the house. Would not recommend unless you have a very well-ventilated kitchen! ReplyCancel

  • Victoria1.15.24 - 5:17 PM

    Just tried it today. 2:30 minutes was enough. 2:45 minutes was too much. It smells STRONGLY for the first hour or so. Be prepared with open windows, doors, ventilation. It will stink up your kitchen. After a couple hours, it barely smells.ReplyCancel

Let's be Pen Pals

Our Pen Pals have direct access to first looks, a peek behind-the-scenes, and exclusive interviews showcasing members of the #YBHDIY community. We can’t wait to connect with you!

Kim and Scott

We’re Kim + Scott, Chicago based content creators behind the Home + Lifestyle brand Yellow Brick Home.

Join us as we renovate and nurture vintage homes across Chicago + SW Michigan!

Instagram iconInstagram icon
Facebook iconFacebook icon
pinterest iconpinterest icon
YouTube iconYouTube icon
Tiktok iconTiktok icon
LTK iconLTK icon

LEt's be Pen Pals

Subscribe for first looks, behind-the-scenes, and exclusive community content

/* footer flodesk form */

This site uses affiliate links. We will always disclose sponsored posts in the text and by using the ‘sponsored' tag.

© 2024 Yellow Brick Home. | All Rights Reserved. | PRIVACY POLICY