How can I UN-attach media from a post?

I’m having a trouble un-attaching media from a post without deleting it entirely from my site. Is there a simple way to unattach an image from a post for instance?

I learned from Brian Fegter that you can Un-attach an image from a post while participating in this question:
Can I attach an image to a different post?

It isn’t exactly “simple”, but not to difficult. It’s the only solution I’ve been able to find.