Answer:
It carries paper of the most important sort but also plastic, I'm glad to report. What is it?
It is a form of plastic money.
If you have me, you want to tell me. If you tell me, you don't have me.
A man goes out in heavy rain with nothing to protect him from it. His hair doesn't get wet. How does he do that?
What is so delicate that saying its name breaks it?
Two little holes in the side of a hill. Just as you come to the cherry-red mill.