Trendy workout clothes may advertise that special silver nanoparticles embedded in the fabric will cut the sweaty odor that builds up from repeated gym visits. It turns out there’s some truth to these claims. Silver can kill the bacteria that cause B.O., and new techniques, including nanotech, allow clothing manufacturers to incorporate silver that doesn’t come out in the wash or harm the environment. In this video, Reactions explains how all of that is possible. And don’t forget: #NationalNanoDay is October 9, and ACS is celebrating science on the nanoscale all week.