stiff armpits on shirts?

[rmayherbs]

My dh's teeshirts and work shirts have, over the years gotten these stiff parts under the arms. I thought it was from him putting on clothes without letting his deodorant dry first, but I am starting to think it is an accumulation of sweat. They dont stink, but the underarms feel like they're made of plastic!

any idea what causes this or how to remove it?

[greencat]

my HD's under shirts get discolored and stiff, if I don't soak them first. I won't know how to remove them, once it gets so hard like plastic, but my first thought is to apply "Oxyclean" on the area that is stiff, and see.