How to remove hardened arm pits from shirts?
I am serious. Many of my tee shirts have become hardened at the armpit area. This is caused by deodorant seeping into the material over time. I am looking for a tried and true method to remove/clean it? No theories please, I have looked this up on google and there are many suggestions how to possibly clean this area "that might work" but I am looking for a product or method somebody has actually used that actually works!