According to this site, you should never combine Castile Soap and vinegar because "They will directly react with each other and cancel each other out. So, instead of getting the best of both, you’ll be getting the worst of something entirely new."
When I saw a claim about how a laundry soap with Castile soap and vinegar was a great laundry detergent I was very skeptical, but had to try for myself.
You Will Need:
1 cup Vinegar (white)
1 cup Baking Soda
1 cup Washing Soda
1/4 cup liquid castile soap
Mix well and store in sealed container. I
find it easiest to pour the liquid soap into the bowl first, stirred in
the washing soda, then baking soda, then added the vinegar in small
batches at a time (the recipe foams up at first). The mixture is a thick
paste at first that will break down into a heavy powdered detergent,
just keep stirring. There may be some hard lumps, try to break them down
when stirring (it really helps to make sure the baking soda isn’t
clumpy when first adding). I used 1/2 cup per full load with great
I used peppermint Castile soap and mixed everything together. I stirred for about 10 minutes while the mixture went from a cottage cheese texture to a stiff powdery texture.
The Verdict: if you read the original directions, the person says, "There may be some hard lumps." What they call hard lumps, I call cement. The mixture was rock solid. I had to get a knife and small hammer to break off pieces to put in my washer.
So even though it worked, if you have to use a hammer with your laundry soap, it's not worth it. Time to try another one.