Sith-Tar.

During the 1800's people used natural gas to light their homes. A wast product of the gas-purifying process was a sticky black substanced called coal tar. The tar was unusable and very often was dumped into local rivers, but today, coal tar is used for medicines, dyes, fertilizers, and other products.

The Jedi Gym! =)

http://www.glumbert.com/media/jedigym