It's called a flint bomb. But what u do is:
First pull off the metal cover in the front. Screwdriver usually works best, but if they're cheap lights u could get away with ur fingers.
Now wrap the lighter in a cloth and pop off the spinny wheel, and a little black piece of flint will come out. It looks like thicker pencil led. It will shoot out so make sure its wrapped in a cloth.
Next take the spring that came out with it, stretch it out with your teeth, then wrap the it around the flint.
Finally hold another lighter up to the flint until it glows slightly orange and throw it against something hard.