Nearly everyone has advised you to wash. I would, however, hope that this is useless information and that you already do this. I play polo and wear tight polo shirts during tournaments and games. I hate the feel of deodorants that you apply daily and they always seem to stain clothes, particularly the Mitchum one mentioned above. To overome this problem, I use a medicated deodorant, which comes in the form of a roll-on. Someones already mentioned this, but they're really good. I'm not particularly sweaty and usual deodorants work fine for me, It's just that I can't stand the feel of them. I only apply the deodorant twice a week, at night. I can't think what it's called, but it's in a small white bottle and is in the deodorant section (funnily enough) at Boots or places like that. Think it's about £7.99. Give it a go, if that fails then you clearly have a problem. If this is the case, visit you're doctor and they'll probably reccommend a series of Botox injections, although I believe this is prescribed in extreme cases only. Hope this helps.