How to Make Organic Dry Powder Laundry Detergent | Home ...- baking powder laundry washing powder washing soap ,Grate your favorite organic bar soap, until you have 1 cup of soap flakes. 2 Combine the soap flakes in a mixing bowl with 1/4 cup of baking soda or washing soda, and 1/2 cup of pure borax.How to Make Organic Dry Powder Laundry Detergent | Home ...Grate your favorite organic bar soap, until you have 1 cup of soap flakes. 2 Combine the soap flakes in a mixing bowl with 1/4 cup of baking soda or washing soda, and 1/2 cup of pure borax.