Which Cleans Better? Liquid vs. Powder Detergent - Bob Vila- laundry soap emon washing powder Machine wash detergent powder washing ,Powder detergent is slightly cheaper. Powder detergent will run you $0.10 to $0.24 per laundry load. The lack of liquid and the lightweight cardboard boxes used for packaging keep the product ...Why you should always use liquid detergent - CNETPowder can also leave chunks of undissolved detergent in your washing machine parts. As you can imagine, this can lead to malfunctions. It particularly affects the washer's drainage system.