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.  If I were able to get my head in there, I’d probably find it throughout.  Is there a way to get this out without scrubbing the thing?
Build Me Up Buttercup

Heather says:

This response focuses on top-loading clothes washers, but the same problem often occurs in front loading washing machines, too. 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.

The best way to deal with build up situations like detergent and limescale is prevention. Regularly cleaning your clothes washer will keep the build-up from becoming significant and difficult to deal with. 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.

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, it is more efficient to apply some elbow grease to the situation.  

Again, making sure that no bleach is present in the machine, spray the agitator and washtub with a dilute solution of white vinegar (usually 50:50 works), give the vinegar some time to dissolve the build-up, and then attack the area with either a scrub brush or sturdy sponge. Thinking about it, it seems as though a NEW—never used—toilet scrub brush may help those of you on the shorter side reach some areas of the washtub. Again, I stress the NEW toilet brush aspect of the suggestion. Scrubbing will help remove what has been loosened by the vinegar.

What you’re doing with the dilute vinegar is dissolving and removing the top layer of scum. Only so much of the build-up can go into solution—your vinegar mix—before it is saturated and unable to dissolve anymore. Once this happens, just rinse it away and spray again. Yay for chemistry!

Science can be cool when it is working for you.

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.

guide to the laundry room
Click the picture for more tips!

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 build up in your laundry. This is caused by one of two problems, 1) using too much detergent or 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.

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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