It isn't always feasible to have a freshly laundered shirt in your office (though kudos to you if you do), so keep club soda and a stain-fighter at the ready. If the stain is stubborn, you can always strategically add a scarf to your outfit.
Tide To Go Instant Stain Remover pens, $8.99 for three, available at Drugstore.com. Witchery Vintage Lace Scarf, $62.16, available at Witchery. Canada Dry club soda, available at your local grocery store.