Answer:
What is black when it is clean and white when it is dirty?
A metal snake that runs on tracks.
Never swallowed but certainly chewed, tossed in the mouth but it is not food. What is it?
Even the oldest ones can be described as current, but a little mainstream.
I cannot be used until I have been broken. What am I?
What goes around and around the wood, but never goes into the wood?