Aparigraha is another yama, referring to non-greediness, or non-possessiveness. This can mean not having more than we need, and also not being so attached to the things we do have.
I have far too many books. Oh how I love them! One of these times I move, I'll have to sell or give away some of my books. I had 37 wal-mart bags full this last time I moved! Mostly paperbacks, some textbooks from college I hope to read again some day, lots of massage therapy texts, yoga books. More than any "thing" in my apartment, I would say I'm the most clingy about my books. I hope to read them all some day, although if there was some way to quantify the amount of time it will take to read them all, I'd probably live several lifetimes before finishing them all!
Yet, even as clingy as I feel about my books, there is a certain lightness toward them. When I imagine letting them go, I think I can do it...