Polyester, nylon or other synthetic fabrics are normally safe to wash in a machine.
Set the washing machine on the gentle cycle with warm water.
Add mild liquid laundry detergent to the wash water.
You can also hand wash the flag with a mild liquid detergent made for delicate items. Frequent use of washing machine for cleaning flag may harm knitting of the fabric.
Pre-Printed Parking for Takeaway Feather Flag - FAQ