Turn the shirt inside out
Rub the mark with a clean microfiber cloth
Use a dry sponge or rubber eraser on the residue
Dab the area with white vinegar on a cloth
Let it sit for a few minutes
Gently rub the fabric against itself
Rinse with cold water
Apply a small amount of liquid laundry detergent to the spot
Let it sit for 10 to 15 minutes
Wash the shirt in cold water
Air dry the shirt
Repeat if needed before drying with heat
Use a lint roller for loose white residue
Prevent future marks by letting deodorant dry before dressing