If it's black, it means the fluid is completely broken down and worn out. At that stage, it has lost all ability to lubricate the components of your transmission.

Thick, white discharge is typical during the menstrual cycle and usually indicate ovulation. However, occasionally it could indicate an uncerlying health issue. Vaginal discharge is a healthy part ...

Black fluid inside your colostomy bag can suggest bleeding in your GI tract. It can also have milder causes, such as: pigments from your food; ...