As time goes by, the mite gets larger and you will start to notice a dirty black substance in your dog's ear. (dogbreedz.com)
This sticky black substance made up of sloughed cells, digestive secretions, and swallowed amniotic fluid will show up in their first dirty diaper. (babycenter.com)
This slow process removes methane, hydrogen, and tar from the wood and reduces the weight of the wood by 75 percent, leaving behind a concentrated, black substance made mostly of carbon. (mindbodygreen.com)