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Traditional Laundry Soap

The modern version of your great-grandmas laundry soap
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Ingredients Method Notes

Ingredients
  

  • 1 bar Fels-Naptha or castile soap bar
  • 1 cup Borax
  • 1 cup washing soda
  • 8 cups of water divided in half

Method
 

  1. Grate the bar of soap and place in a heavy pot.
  2. Add 4 cups of water.
  3. Heat on low until the soap is completely melted (don’t let it boil - big mess!)
  4. Once melted, remove from heat and add in the Borax and washing soda.
  5. Stir until the powder is dissolved. Be patient, it may take a bit.
  6. Add the remainder 4 cups of water.
  7. Once cooled, use an imersion blender, hand mixer, or blender to futher work it so it can emulsify to avoid separation.
  8. Store in a glass jar.
  9. Use 1-2 tbsp per load.

Notes

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You can view my DIY MODERN LAUNDRY DETERGENT recipe HERE
Notes:
  • When melting the soap, DO NOT let it boil. It will suds over and you may have a super clean stove-top, but a huge mess to clean up!
  • It does take a bit for the powders to dissolve - so be patient. If you don’t blend the final product, sometimes there’s a top layer due to separation.
  • Stir well or shake the jar before measuring out for a load of laundry.
I chose to share this recipe because it is a old-fashioned formula used from generations past. It simple, quick and gets the job done. Please read the following information below to understand more about this laundry soap and its differences from the modern day detergent.
  • This recipe makes laundry soap, not a modern synthetic detergent.
  • If you don’t blend it once it has cooked, separation is normal. The soap may form a solid layer on top or become gel-like as it cools. Simply stir or shake before each use.
  • Hard water may cause additional separation or leave soap residue on clothing.
  • This recipe may not perform as well in HE (high-efficiency) washing machines or for heavily soiled loads.
  • Store at room temperature. If it becomes too thick, warm gently and stir.
  • Since this recipe contains Fels-Naptha, it is best described as low-tox rather than no-tox because the soap contains fragrance and other manufactured ingredients.
  • You can also use an olive-oil based castile soap bar or coconut oil soap bar.
MORE INFO:
-This can be made and kept dry or made the way you see in the video - into a liquid/solid. I prefer the liquid method as it is best for me and my machine.
-Use caution if using in an HE machine. They use less water and may not be able to fully flush the soap down the drain. Many successfully use this in HE machines - and just flush the pipes after a wash cycle.
-This soap is no longer the original recipe - and it seems many don’t know this. Fels-Naptha has been reformulated several times over its long history. A documented change occurred after Purex acquired the brand in 1964, and the original naphtha-containing formula is no longer what is sold today. Summit Brands acquired the brand from Henkel in 2022, and many long-time users have reported noticeable changes in the newer bars.
-Today’s Fels-Naptha is not the same product your grandmother would have used. It has been reformulated over its history, including said documented change after the 1964 Purex acquisition. The current product no longer lists naphtha, but it still isn’t something I’d label “non-toxic” or “healthier” simply because it’s a newer formulation.
That being said, it is still used and loved by many in simple, homemade laundry soaps.
I have found that either people love or hate this recipe because of the Fels-Naptha. I say, let everyone make their own choice on whether they choose to use it or not.