Rinse the stained area with cold water as soon as possible
Mix equal parts white vinegar and water
Soak the stain for 15 to 30 minutes
Gently rub in liquid laundry detergent or dish soap
Sprinkle baking soda on the stain and add a little water to make a paste
Let the paste sit for 15 to 30 minutes
Wash the shirt in the hottest water safe for the fabric
Check the stain before drying
Repeat the treatment if needed
Avoid using a dryer until the stain is gone
For white shirts, use oxygen bleach if the fabric allows it
For delicate fabrics, test any cleaner on a hidden area first