Your sweat is a concoction of oil, dead skins cells, and bacteria that clogs pores. That's why it's essential to shower after a particularly raunchy day. The good news is that perspiring is a great way to purge bacteria from your pores, but make sure that you rinse those impurities away so it's not reabsorbed through the skin. If you can't get to a shower right after exercising, don't fret — just stash an oil-controlling body spray in your gym bag for post-workout touch-ups.