To properly wash a soccer jersey, you should follow these steps:

1. Start by checking the care label on the jersey to see if there are any specific washing instructions.
2. If the jersey is very dirty, pre-treat any stains by rubbing a small amount of laundry detergent directly onto the stain.
3. Turn the jersey inside out to protect the colors and design on the outside of the jersey.
4. Place the jersey in the washing machine, along with other similar-colored items.
5. Use a mild laundry detergent and set the washing machine to a gentle cycle.
6. Avoid using bleach or fabric softener, as these can damage the jersey and affect its performance.
7. After washing, hang the jersey up to air dry. Avoid using a dryer, as this can shrink the jersey and cause damage.
8. Once the jersey is dry, fold it neatly and store it in a cool, dry place.

By following these steps, you can ensure that your soccer jersey is properly cleaned and maintained.