How to Remove Detergent Build Up in a Washing Machine

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Dear Home-Ec 101,
I’ve recently noticed a layer of scum around the agitator.  I’d probably find it throughout if I could get my head in there.  Is there a way to get this out without scrubbing the thing?
Build Me Up, Buttercup

This response focuses on top-loading clothes washers, but the same problem often occurs in front-loading washing machines. Please note that front-loading clothes washers do not have an agitator.

What you’re looking at is most likely a layer of detergent build-up that occurs when suds are splashed onto the agitator or other parts of the washbasin, not normally under the waterline. Just like soap scum builds up in your shower, the water evaporates, leaving behind a residue that we often refer to as soap scum. In areas with hard water, the problem is exacerbated by limescale, which refers to mineral deposits also left behind.

Also, what you see is not the only place this residue has been building up. The basket, the part your clothes sit in, actually sits in a drum, kind of like a bucket. The outside of the basket and the inside of the drum can have significant build-up that you will never see, but you might smell.

The best way to deal with build-up situations like detergent, biofilm, and limescale is prevention.

Regularly cleaning your clothes washer will keep the build-up from becoming significant and difficult to deal with.

If you live in an area that isn’t known for very hard water, you can get away with doing the following once a month:

Once a month, run an empty, large load with 2 – 4 cups of white vinegar, depending on the machine’s capacity. The vinegar’s acidity helps dissolve the detergent and limescale build-up that may accumulate on a washing machine’s agitator and washtub.

However, if you do a LOT of laundry, have never removed build-up before, or live in an area with hard water (or some combination of the above, you will need to start by doing this process more than once and then every couple of weeks. 

For safety’s sake, do not use this cleaning method immediately following a load in which chlorine bleach has been used.

Bleach and vinegar should not be mixed.

Do not add vinegar through the bleach dispenser.

If you want to be extra cautious, add water, through the bleach dispenser, to the load before the cleaning cycle.

In your case, it sounds like the detergent build-up has been accumulating for some time; one load may not be enough. If this is the case, even though you said you didn’t want to, applying some elbow grease to the situation will be much more efficient.

What about your washer’s existing detergent, bio-film, or limescale build-up?

I know you said you didn’t want to, but you may find it most effective to scrub out everything you can reach first. Why? Chemistry. Only so much “stuff” can be taken off of your washer with chemicals and rinsed away. Scrubbing will physically remove the build-up. Chemicals will make your job scrubbing easier, but won’t remove all of the effort.

You can start with white vinegar diluted to 50:50 with water. If that isn’t working, you may want to step up to stronger measures such as CLR. (Calcium Lime Rust Remover).

Please wear gloves while working.

Run a plain water rinse between your vinegar scrub and when you try CLR. Additionally, run another rinse and spin cycle before washing clothing.

Once you have removed all visible scum, it’s time to break run a cycle with a washing machine cleaner.

How to prevent detergent build-up in the future

To help prevent this problem from reoccurring, use a simple test to see if you’ve been using too much detergent or overloading your machine.

Take a clean, dry towel and place it in the empty washtub. Set the washer for a small load on hot. Allow the towel to agitate for a few moments. Open the lid and look in. If you see suds, you have detergent buildup in your laundry.

This is caused by one of two problems:

  1. Using too much detergent
  2. Overloading the machine so it cannot be rinsed properly.

Check your manual to determine if you have been overstuffing the machine, and experiment with less detergent if it is the prime suspect.

Remember, if you have a high-efficiency washer, you should not use more than two tablespoons per load.

Happy laundering!

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7 thoughts on “How to Remove Detergent Build Up in a Washing Machine”

  1. An even better solution (and I have no interest in or connection to this company) is to use Charlie's Soap, a terrific, no-frills detergent that leaves no buildup and even removes the buildup from your old detergent. In fact, the company advises first-time users to run an empty load (or a load of rags) to avoid having that gunk transfer to your clothes. Charlie's is environmentally-friendly, works great, and takes only a tablespoon per load.

    When I first started using the stuff, I bought it directly from the company, and they didn't charge for shipping. But as they've built out their retail network, they're trying not to compete with it. You can find retailers that carry the product at their web site, They also make a liquid detergent and a household spray cleaner.

    I highly recommend it.

  2. Thanks for the tip I'm going to give this a try today. I've also noticed a slight stale smell in my top loading washer. I always keep the lid closed because we have four cats who sometimes like to get into things. Don't know if the smell is having the washer 'closed' all the time/the buildup/ or both. I do use my washer on almost a daily basis.
    My recent post Late Night Surfing

    • Part of the answer depends on the climate in your area. If you live in a really humid area like I do, it's more important to leave the lid open to encourage air flow and drying.
      Top loading washers aren't as tightly sealed as their front load counterparts, if you live in a dry climate, the airflow that can get in anyway may be enough.
      A musty smell is usually a sign of mildew. So in your case, it sounds as though leaving the lid open is probably a better choice. It's that or a more regular and thorough cleaning of the machine.
      Cats amuse me with their antics. Thankfully I only have to deal with that vicariously – my allergies will never let me be a cat person.

      • I too have cats. I prop top open w empty water bottle overnight. Barely enough room to let them under it besides they push on it they will dislodge bottle and it will close. (I also have door in laundry room). Once dry I give Light must w Lysol spray and shut. Always fine when I open 5-7 days later. I do all laundry once a week…

  3. I seem to have an issue with bleach spots on some of my clothes especially my husbands any ideas on what this could be from?

  4. Is there a tool or brush that can be recommended for cleaning soap scum residue from the agitator and its many curvy, over and under and other hard to reach places?

    • Just got finished scrubbing down the washer. Had to remove screws to lift the lid. Lots of gray scum spots. Amazingly the hack I have found on uses for used dryer sheets scrubbed it away with little elbow grease. I am planning to keep up with monthly cleanings and pay attention to detergent amounts and load sizes. Is powdered detergent better than the liquid?


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