Answer:
You throw me out when you use me and take me in when you are done.
I am the kind of nut that is empty at the center and has no shell.
My teeth help me suck.
Lighter than what I am made of, more of me is hidden than is seen. What am I?
I have three feet but no arms or legs
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.