Watch the video ^
I've always heard that if there's dirt on the top of the battery it will drain power from the car battery. I had a really dirty battery so I figured I would run the test and see if it was true. When I put my volt meter on the positive battery terminal and the top of the dirty battery there was about a 4V drain. Once I clean the battery that drain was gone. So it appears that it's a good idea to clean the top of your battery to stop power from draining off. I would imagine there aren't very many amps going through the dirt and Grease on the battery but that would be another good test to try. If you have any comments please feel free to let me know any of your thoughts.