Washing soda can be found in the laundry section of stores like Target, Walmart, and some well-stocked grocery stores or online. You can buy citric acid in the pharmacy or canning section of grocery stores or online. To make powdered dishwasher detergent instead of tablets, eliminate the water and store the powder in a large container or jar. Use 1 tablespoon per load. Distilled white vinegar is a great rinse agent. Just pour it into the receptacle in the dishwasher.