How to Prep Cloth Diapers: Your Questions Answered

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Not all cloth diapers are made from the same material, therefore not all cloth diapers can be prepped in one single load.  I’m answering the most common questions I’ve been asked over the years in hopes that I can just refer future readers here and save my hands some typing.  Just kidding…  kind of.  If you are completely new to cloth diapers you will find a lot more helpful information on my New to Cloth Diapers.

So exactly what does “prepping” mean?

Prepping is the process of washing your cloth diapers repeatedly before the first use in order to help them reach their maximum absorbency.  Prepping will also remove any excess natural oils from the diapers (those with natural fibers) and clean away any dirt left over from the manufacturing process.  

Do I have to prep my diapers?

Yes, at least once.  If only to remove any leftover chemicals that might be present on the diapers from manufacturing.  I always wash my diapers at least one good time before using them, just in case.  If you do decide to only wash once then use that diaper during the day and not for a nap.  It won’t be fully absorbent until it gets washed a few more times.

Can I wash my synthetic cloth diapers with my diapers made with natural fibers?

No!  Cloth diapers made from cotton, bamboo, and hemp will have a natural oil in the fibers that will wash away within the first few washes.  Organic, unbleached natural fibers (especially organic cotton) have even more oils.  These oils can wash onto your synthetic materials, especially the stay dry layers of pocket diapers made from microfleece and suedecloth, and leave a build-up that leads to repelling (when liquids don’t absorb).  All natural materials should be washed at least three times alone.  If you receive a pocket diaper in the mail that comes with a hemp insert you still need to wash those two pieces separately.  I have a materials glossary for cloth diapers if you need a reference.

How many washes does it take for a diaper to be fully prepped and absorbent?

There is no definite answer because every diaper is made from a different material, however an average number is 6-8.  Microfiber inserts will fall on the lower range, even less than 6 usually.  Natural materials, especially hemp, will take 8 washes.

Do I need to dry the diapers between each wash when prepping?

Eh……..  I don’t.  The drying will exponentially increase quilting (this is when the cotton puffs/wrinkles up which makes them more absorbent) when prepping prefolds, however I don’t find this necessary for other inserts or diapers.  So basically- inserts, flats, fitteds- no.  Cotton prefolds- yes.

Boiling a load of flats

Can I boil my diapers to prep them faster?

You can, but take my advice:  don’t unless you understand what you are getting into!  Boiling looks like the easy route but unless you have a witch’s cauldron or you only need to boil a handful of diapers you’ll want the capacity of a washer.  I gave my tiny apartment kitchen a steam bath when I boiled about 52 prefolds in batches.  It took 5 hours of constant work.  The steam “cleaned” my wallpaper, leaving disgusting yellow streaks down my walls.  I ended up doing even more work than just boiling diapers- I also had to wash all of my walls.  You can NOT boil any parts of a cloth diaper that have PUL, TPU, elastic, or snaps.  Really the only things you can boil are prefolds, flats, and inserts.

What if I just have one brand new diaper?  Do I really need it wash it all by itself to prep it? 

This will all depend on the materials.  If it has organic, natural materials, I defintely would still wash it by itself.  This will be less work than stripping all of your diapers later.  If the diaper is made from synthetics,  non organic cotton, or non organic bamboo velour then I would say it should be ok and you can sneak it into a load of your dirty diapers.

How much detergent do I use when just prepping my diapers?

There is conflicting information on this (just like all diaper washing articles) but I use the tiniest amount.  Usually just a teaspoon or two.  Since prep loads are usually less than full wash loads this gives you enough to work out the oils but not enough to cause any repelling problems.  Some people prefer not to use any soap.  You can adjust the amount if you are prepping an entire load of brand new diapers- so if you have a full wash load of 12-15 new diapers you could use the full recommended amount by your soap maker.  In my case it would be 2 tablespoons of Rockin’ Green.

Do I need to prep my new covers?

Covers aren’t absorbent therefore you don’t need to “prep” them in the sense that they need washing to work effectively.  They will work right out of the package as intended.  You will still probably want to wash once but you can throw these into your dirty laundry (if you have any).

Should I prep my “new to me” (previously loved) diapers?

Assuming they were loved more than a few times they will already be fully absorbent.  You might want to “strip” your diapers, however.

Stripping gone wrong- Image from a friend

What is “Stripping” and why does it sound so dirty?  

Stripping refers to the removal of any soap, minerals, and stink that sometimes accumulate over time in the fibers of cloth diapers.  All fabrics cling to these things during the wash but unlike cloth diapers, our sheets and clothes don’t need to hold liquid so this isn’t usually a concern.  When stripping diapers there are several approaches, some of which could void the warranty of your diapers, so do your research and understand what you are getting into.  The simplest form of stripping just involved repeated HOT WASH CYCLES with no detergent.  The hot water will remove the built up soap and rinse it away.  Other stripping methods will recommend using Original Blue Dawn (just a drop…) and bleach.  If someone tells you to strip your diapers using your dish washer- DON’T DO IT.  This is extremely unsafe since a diaper could land on a heating element inside and start a fire.  Not only that, but you can potentially ruin your diapers.  If you are looking to go the unconventional route read about how to use fish tank ammonia remover.  Why does “stripping” sound so dirty?  Because your mind is in the gutter, that’s why!

How will I know that my diapers are fully prepped?

There won’t be an exact moment where you look at your diapers and know for certain that they are fully absorbent.  With prefolds you can kind of tell by how quilted the cotton appears, but even at full quilt they will still become more absorbent for a few more washes.  With pockets, All-in-Ones, All-in-Two’s, Fitteds, Flats, and other types of cloth diapers you’ll just have to work on the honor system.  If you decided to only wash once and let the dirty washes do the rest of the work give those diapers a few weeks or even a month before trying them overnight.  You won’t want to use a half-prepped diaper overnight because you’ll likely get unfavorable results.  Don’t rule out a diaper if it leaks and it is new- chances are it just needs a few more washes.

Do you have a prepping question that wasn’t answered?  Leave a comment and I’ll answer it if I can!

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Kim Rosas began Dirty Diaper Laundry in 2009 out of a desire to help more parents understand modern cloth diapers. She lives in Florida with her husband of 5 years and her two boys. Even though none of her boys wear diapers anymore she is still just as committed to promoting them. In her spare time Kim enjoys video editing, photography, and coffee.
  • Nicole U

    Great information! I learned just a little detergent is great to use while prepping.

  • megan

    Pocket diapers not the inserts. Should they be washed and prepped in hot or cold water?

  • TB

    I’ve got a brand new lot of organic bamboo pocket diapers coming in organic bamboo inserts, a few hemp inserts for overnight, and a few heavy wetter TPU pocket diapers with along with 8 unbleached microfiber inserts.

    We also have some hemp/organic cotton inserts and wipes for baby in that material(s.)

    Should the Thermoplastic Polyurethane (TPU) Laminated Fabric pocket and microfiber inserts be washed together in one load then the rest of the natural fabric lot be wash in its own load? We only have 8 microfiber inserts and 4 TPU pockets so it’d be a very small load.

    When you prep them (6-8 times) do you had a lil detergent every time or just in the first wash then the rest of the (5-7 times) without detergent?

    Thanks for any help. WAHH that learning the ropes in cloth diapering.

  • Mel

    Hi, I’m a mom to 3 (last one is 3 months old) and getting ready to try my hand at cloth for the first time! I purchased Alva pockets with bamboo inserts. I know that there is no “right” way to do it, but just seeking out ideas/opinions from others to get me on the road at least. Will 1 bamboo insert be enough absorption for now or will I need more? I understand that as they grow/pee more, you’ll need more layers, but just don’t know if 1 is where I should start or is 1 insert never enough?? I appreciate ANY advice offered! Thanks!!

    • kimrosas

      It depends on how many layers it is and your baby’s output. If it seems thin and flimsy you might need a second insert but there’s no way to know until you try them.
      Please excuse typos and brevity. Sent from my iPhone

  • Melanie Bailey

    what is the best detergent to use that can be purchased from a retail store?

  • ali

    So washing non-organic cotton and organic cotton together is okay, or not a good idea since they both have oils in them, but organic has more oils?

    • kimrosas

      Probably up to your personal discretion… I really avoid organics with others but the non-organics have likely been bleached and therefore lack the amount of oils that could wash onto other items.

  • Karen Jones

    do you use detergent for prepping?

    • kimrosas

      You can, just a small amount.

  • Yan

    i’ve made a 100% cotton insert by my self. How many washes do i need to prep it? By boiling will be enough?

  • Olivia

    Is there a different wash method for every load? I just recently used baking soda, sea salt and vinegar together at once. But I don’t believe I’m suppose to use that everytime. What other ways is their that won’t damage my diapers? I wash once a week, though I’ve heard it should be every 2 to 3 days.

    I am new, but could still use a lot of help! I will read the article above about new to cloth diapers, but still input is nice!


  • Wdrewes

    I have bought silky cloth pocket diapers with microfiber inserts and was wondering how I need to wash & prep them (diapers and inserts the same?)? We have an “HE” washer so I’m not sure what kind of detergent is best for the “HE” washers as well as the cloth diapers? Also, do all of our baby clothes need to be washed with the same detergent as the diapers?

  • Alicia Nicole McDonald

    How do I strip my diapers. Can I use vinager

    • kimrosas

      Stripping is done by doing several hot washes with no detergent, and possibly adding a small amount of bleach to disinfect if needed. Vinegar is not recommended.

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