Here’s a tip from a home made product that I have used for years in my homemade soap powder for clothes washing.
Take one cup of regular arm and hammer baking soda(that you buy in the baking isle).And set your oven to 400 degrees.
Place powder on a cookie sheet and bake for 45 min.(I do turn on my stove fan) as while the chemical change is taking place from baking soda to washing powder) does have a small odor in the air.This is to be kept in a closed container as it will revert back to its original form (for baking soda)if it gets any moisture in it. This is the single batch size for most homemade washing powder recipes that you find.
It saves me a lot of cash,not having to spend $8.00 for the cup of arm and hammer clothes washing powder on the store shelves.I buy the largest baking (SODA) in the baking isle to use for many things.
Love to you all.