I vote for Wet Ones, or whatever the kids are calling moist towelettes these days. These usually have some sort of rubbing alcohol in them to kill bacteria and leave you freshened. Slap on some fresh deodorant and you're good to go. If there's any way you can cool down before changing into your work clothes, do so. I arrive early to work and chill at my desk for a few minutes, then go and change. I rarely [if ever] have to worry about sweating in my work clothes.