Answer:
Cold head and feet; round as a ball; always turning around myself.
I open to close but I close to open. I'm surrounded by water but I'm never soaking. What am I?
The more you take away from me the bigger I shall get.
Flat as a leaf, round as a ring; have two eyes, can't see a thing. What am I?
At night I come without being fetched, and by day I am lost without being stolen. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.