If you're looking for an opportunity to make some extra cash with something you have been doing for free all your life, you're in luck.

You can now donate your poop (healthy samples only) in the name of science.

You can donate blood, plasma, eggs, and sperm. Why not poop? Your feces are perhaps your greatest untapped monetary resource. Thanks to a nonprofit organization called OpenBiome, you can cash in to the tune of $13,000 a year -- and save lives while you're at it. (WaPo)

The company pays $40 for each accepted sample. There's a  $50 bonus for those who agree to provide samples five days per week.

EliteDaily describes the process:

The samples go to aid those with Clostridium difficile, an infection, commonly acquired in hospitals, that causes inflammation of the colon.

The donations are frozen, then are implanted in the patient's gastrointestinal tract by way of capsule or endoscopy.

But don't dream of a poop-paid vacation just yet. The Washington Post reports that OpenBiome has very stringent guidelines when it comes to potential donors. Each candidate undergoes an extensive screening process, with only about 4 percent of applicants making the cut. Donors also have to provide samples in person at the company's  Medford, Mass. office.

According to The Washington Post, the company has shipped about 2,000 treatments to 185 hospitals around the country.