Those 40,000 volts cause the spark plug to emit a spark and light up the air/fuel mixture. However, if these little plugs become contaminated by oil, they can malfunction, or worse.

Let's say you've just removed an old spark plug. Does it have any life left in it? Can it be reused if it is cleaned properly? Let's take a closer look.

In addition to your spark plug socket, you'll also need a variety of different sized standard sockets, a ratchet, and some extensions. That's because even if you drive a car with an engine that ...