|I use 3 in a linen bag with a few drops of scented oil. I leave it in the whole cycle. Since the rinse water is cold & soapnuts need warm or hot to work well, no worries about it being wasted in the rinse water.
3 nuts does 5 loads of our family's laundry.
I use 2 nuts for diapers, but use fresh nuts each time. I use the "diaper used" nuts on my towels after. I just figure washing on super-hot heavy duty cycle probably uses up more of them faster. I have no proof of this but I have used soapnuts exclusively for 100% of our laundry items for 10 months now with no issues.
I have made "stain concentrate" for pre-treating clothes.
You can make all kinds of stuff with soapnuts. Shampoo, handsoap, stain remover, etc.
My favorite informational site for recipies & supplies is laundrytee.com
Check it out. Even if you don't buy from her, she has great information!