The ink gets all stiff and gunky and doesn’t transfer to the ball. The ball might not even spin at that point. Lick it.

Usually this means the ball part is stuck and/or the ink surrounding it has dried out.

Here’s a close up of how they work: https://youtube.com/shorts/7KGqGAlxwJs

If no ink gets transfered unto the ball, it’s not able to write anything.

By design by Big Pen

I know that you can use a cigarette lighter, very briefly, to burn off the stuck-on ink off the ball… otherwise the ball will pop out because the ink behind it turns to steam, I assume.

I believe there’s a chemical (maybe isopropyl alcohol?) That you can apply to the ball to dissolve the ink as well.

Why can my car stop running forever when there’s still a full tank of gas?