Flints are something that need to be replaced, approximately every few weeks for an average user.
To replace the flint we need to remove it from the flint tube:
1. First, remove the inside unit (insert) from the case.
2. Turn it over and unscrew the flint spring using a small screwdriver or a coin. Slowly remove the spring.
3. Turning the inside unit (insert) right side up again, remove the remaining piece of flint, if any, by gently tapping the inside unit on a hard surface.
4. Insert a new flint in the brass-colored flint tube. Be sure not to confuse the brass tip on the end of the flint spring. Even though it looks like a flint, it is not a flint.
5. Replace the flint spring and turn clockwise until tight.
6. If the flint wheel binds after a new flint is installed, turn the wheel backwards a few times.