I spent some time stuffing those bags at two recent conferences (a good way to meet the people who make the conference happen by the way) and a lot of years getting them at conferences and cons.
Mostly I throw the stuff away. Sorry. I know it pains your heart and wallet to hear. I toss postcards, pens (I have a certain kind of pen I like) and gum. I toss the flyers after a quick once-over. And I mostly leave the books on the give-back table cause I don't want to pay to ship them, and I don't want to haul them.
In this I am probably an anomaly.
There's one swag item I've actually used a lot since I got it and I think it's a terrific item for swag bag:
It's lip balm with the book cover for Hank Phillipi Ryan's THE OTHER WOMAN. I'm more aware of this book than almost any other these days cause I'm looking at this cover a LOT.
Smart girl our Hank!