I got TONS of them when we first moved into this house. They were in every room, sometimes more than once (the people who lived here before us...the mom and her two daughters apparently never met a scented product they didn't like. Our middle bathroom STILL smells like them), trying to just dilute the old owner smell. They didn't do a thing. If I got right on top of one, I could maybe get a little wiff of something.
I'm finding it's just more effective to burn essential oils.