How to Wash Flags
Whether it is your national flag or a custom flag or a decorative garden banner, washing your flags on regularly can extent its life expectancy. Almost all outdoor flags are made of nylon or polyester; but cotton flags are still sold. The safest way to wash a flag is to handwash in cold water with a laundry detergent.Test the fabric first if you are not sure if the fabric is colorfast. Rub each color on the flag with wet cotton swab. If any dye transfers to the swab, the colors will bleed when the flag is washed. You are better off to just buy a brand new flag.
If there is no bleeding of any color, you can securely wash the flags in a regular washer. Set the washer to gentle and always use cold water for the wash and rinse to reduce color bleeding.
Do not dry your flag in a hot clother dryer. Instead, hang it up on a drying rack. If it is wrinkled, use a cool iron to press nylon flags and a hot iron for polyester and cotton flags. Polyester fabric can take up to 150 degrees celsius before we see any fabric heat deformation
If you are not sure about the fiber content of your flag or if it is vintage, take it to a dry cleaner. Many offer free American flag cleaning services, especially in the month of July.
How to Remove Stains From a Flag or Banner
If your flag or banner has tree sap stains or is dirty from the outdoor elements, use oxygen based bleech. Submerge the flag in a sink full of bleech . Let it to soak at least four hours and then launder. Oxygen based bleach is safe for white or colored fabrics, natural or synthetic. Repeat the process if the stains are not gone.