I’ve got some white t-shirts that have graphic prints on the front, that are stained in the armpits. I was wondering if I could bleach just the armpits of the shirt? I was thinking if I rinsed the bleach off the pits before washing it wouldn’t damage the rest of the shirt, but I’m not sure if there’s a better way of dealing with pit stains. Thanks in advance.
Shirts are cotton if it matters


Take a small cooler. Fill it with very hot water. Add one cup powder oxi clean and one cup powder detergent. Must be powder. Fully submerge shirt(s) and let sit 24 hours.
Next day take out clothes wring out extra water and put in washing machine. In the bottom of the machine or in detergent dispenser put powder detergent. On top of clothes and not touching detergent put 1/4 cup ammonia.
Wash and rinse. Good as new.