See, when you draw something with a pencil, and you don’t like it, you use an eraser, but you might wonder how it works.
This is how an eraser works:
When you rub the eraser on the paper it picks up pencil lead, some erasers actually break the surface of the paper.
The eraser’s molecules are stickier then the paper’s, so pencil lead goes on the eraser.
BTW, pencil lead isn’t lead, it’s graphite.