Answer:
What cleans as it gets dirty only to get clean the more you use it?
What goes up and down the stairs without moving?
What has no hands but might knock on your door, and if it does you better open up?
Sheets of paper that tell new stories each day.
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.