Step 1: Pour white vinegar into the basin (white vinegar contains acetic acid, which can decompose the residual detergent dirt on clothes).

Step 2: Then pour baking soda into the basin (baking soda has the function of decontamination).

Step 3: Soak the clothes stained with washing powder in a basin for 5 minutes.

Step 4: Then carefully scrub the residual detergent dirt on the clothes.

Step 5: After the clothes are dried, there are detergent stains on them and they have been cleaned.