Thanks to all who replied! I will be trying the dishwashing soap idea or maybe the ivory soap idea.
I had no idea it could get so complicated
Basically, I need to hand felt before sewing together -- the hand felting instructions say not to use laundry detergent but use laundry soap.
This is for a toy project.
I had to laugh when I read that little detail in the instructions because I figured it would be a real challenge finding the stuff. I know there is a manufacturer out there who still makes the stuff. The last time I saw laundry soap was on my great grandmother's laundry shelf in the Oklahoma panhandle decades ago. Of course the kid at Walmart gave me a funny look when I asked where the laundry soap could be found while standing in the laundry detergent aisle. I could just hear his thoughts, "Sheesh, lady! What a stupid question!"