In the past year or two I've put together a decent collection of shirts made from high quality fabrics. I used to wear undershirts 90% of the time, but one of the selling points of nicer fabrics is their silky feel on your skin. Now I wear most of my shirts without undershirts, but I'm worried about deoderant stains. My undershirts (PRL 100% cotton), though admittedly much tighter-fitting than my dress shirts, inevitably develop discolored stains in the armpit region due to the chemical (aluminum oxide?) that is present in pretty much all deoderants. Has anyone here had this problem? So far my shirts are unscathed, but I can't help but worry about their survival in the long term.