Haha. Yes, as a sometime property manager (not my airbnb listing) I've had renters who, when they were moving out and I saw all the junk they were leaving behind and said, "Oh don't forget all those bent hangars and the cracked blender container", said, "Oh, you can have that stuff."
It's called lazy and irresponsible for their own mess.
I'd give her a low rating for cleanliness and send her a personal message letting her know that no one considers garbage left behind to be a "gift". However, if she was an okay renter in other ways (respectful of house rules other than cleaning up after yourself, not demanding or nasty), I'd add something positive as well in the personal message. People take criticism better if it comes with some praise in other regards.