I was told to just cut the card up. Shame, I used to carry fake/old cards in my mugger's wallet when I used to go out boozing.
I look for anything and everything that is of use. Furniture, plant pots, plants, timber to make stuff out of. I got a nice desk and a bedding cabinet and a funky hat stand recently. My whole garden is kitted out with other people's discarded stuff and rescued plants. It's a bit eclectic but kind of cool.
Oh and stones, lots of old dressed stone, dragged back and used to landscape the spare bit of land near the garages. There are loads of old bits of stone around here from collapsed Victorian buildings.