I learned this handy dandy little tip in the theatre. During a performance week there is usually neither the time nor the money to dry clean those costumes that happen to require dry cleaning. Our Union requires that all skins (those pieces that are in direct contact with your body like socks, bras, slips etc) be washed daily. The costumers will also kindly wash anything that is washable, as well, but that leaves some other very smelly unwashable clothes to be worn for the week, until they can be cleaned. That can be up to 9 performances. Not very pleasant for anyone involved.
So what they do is spray the costumes, particularly the malodorous spots under the arm with undiluted vodka (the cheaper the higher proof the better). Some will use Febreze, but the Vodka seems to work better, and is a more environmentally friendly alternative, I would think.
So, next time you can't wash a particular item and it needs a little freshening up, try some vodka. Seems like that might be a good travel option, when you are traveling light and are unable to wash every day.