According to Clorox, ring around the collar stains on white shirts can removed by pre-treating the stain with mild bleach, followed by a hot water wash with 1/2 cup of bleach and regular laundry detergent. Ring around the collar stains on colored shirts can be removed by pre-treating the stain with color-safe detergent, followed by a water wash. Colored shirts should be washed in the temperature recommended on the label.
In addition to bleach and color-safe detergent, ring around the collar stains can also be pre-treated with spot cleaning stain sticks and laundry sprays that contain solvent-based stain removers. It is important for individuals with dry clean only fabrics such as silk, mohair and leather to advise their dry cleaning consultants of the collar stains to ensure the garment is treated properly.
Ring around the collar stains occur when sweat combines with body soil on the neck and rubs off into the shirt collar. Collar stain build up is preventable with regular pre-treating of shirt collars after each wear. It is also important for individuals treating ring around the collar stains to air-dry their shirts until the stains are completely eliminated. Stains that have developed over time often require more than one treatment.