You throw me out when you want to use me and you take me in when you don't want to use me.
Who am I?
If I have it, I don't share it. If I share it, I don't have it.
What is it?
I give milk and have a horn but I'm not a cow. Who am I?See answer
Select a pack of riddles and try to solve it in an interesting way.
This riddle appears in the following downloadable PDF files: