Depends on how hot and sweaty I get. I have access to a shower at work and take advantage of it pretty regularly in the summer. Other times of year, I'm more likely to just rinse off in the sink. For alcohol, another suggestion is hand sanitizer. If your building's like mine, there's some in dispensers in the restrooms. When I'm changing, washing up in there, I put a few squirts on some paper towels, add a splash of water and clean off the armpits, behind the ears, and other critical areas as needed. It works well and keeps me from having to actually carry any rubbing alcohol with me.

I wear wicking fabric tee-shirts as a base layer all year round, and as the only layer in the hotter times of year. For shorts, I also often wear swim trunks. If not that, then I wear underwear and athletic shorts.