These merino-wool t-shirts are proving to be excellent. They are comfortable, lightweight and airy, and don't get all heavy and wet from my sweat. The big salt stains from my sweat are hidden somewhat by the flecked appearance of the grey fabric.
Soaking my hair with water feels great since I haven't had a shower in five days and don't usually have enough water at my campsites to "waste" on serious washing.