bookcase curtains

[grimms-creed.livejournal.com]

So I want to put some curtains onto my many overstuffed bookcases. Something to over the mess and make things pretty. But I can't seem to figure out how. It has to be something that will still let me get to my books when I want to (there's a reason they're so overcrowded!) and that I can take down to wash without too much hassle, since I have allergies.

Anyone have ideas?