Can you post how to do this?!
I googled it before I did it. The method I used was to fill a bucket with some bleach and had the bottoms of the shirts in the bleach. Then like every 10 minutes or so I added a few cups of hot water. Once they got to a place that I was happy with, I rinsed them out in the tub and then put them through the wash.
Next time I think I’m going to wet them first. Also, do it outside if you can. My whole apartment reeked of bleach and my roommate was not too pleased.