There are very few methods humans can use to get rid of chemicals from the body: pooping, peeing, exhaling, and sweating it out. In us humans, sweat glands are known mostly to help regulate temperature by bringing warm moisture to the surface of the skin, which causes cooling as the water evaporates. But the secondary role as detoxifier is not a minor role. Known as the 'third kidney,' your skin has over 2.6 million tiny pores that can help clear as much as 30% of bodily wastes through perspiring. Sweat is composed mostly of water, but also has urea (a breakdown product of proteins the kidneys also discard), and trace metals and minerals.
Although experts believe sweating is mostly for temperature regulation, it has been shown that trace toxins do appear in sweat glands. Some evidence does suggest that the ability to sweat and excrete toxins like mercury will increase with repeated use of exercise or sauna.