1. First prepare a plate of warm water with a temperature of about 35 degrees, as shown in the figure below.

2. Then, add 100 ml white vinegar to warm water, as shown in the figure below.

3. Stir gently by hand, as shown in the figure below.

4. Put the sweater in and soak it for about 30 minutes, as shown below.

5. When the time is up, gently stretch the sweater with your hands, as shown below.

6. After pulling the whole sweater, wash the sweater with water, as shown below.

7. After cleaning, wrap the towel on the sweater and gently press out the water, as shown in the figure below.

8. After finishing, dry the sweater in the shade, as shown in the figure below.