If your house was built before 1980 it probably has an old antenna on the roof. You may not be using it at all, but is it worth it to try to make some money off it?
Before taking an antenna off the roof, inspect it thoroughly. A lot of older antennas still work great, and even if an element or two is bent they still do fine. Those bent elements can even be bent back into place with a little time and effort. Every TV antenna made for US broadcasting will still work with the new HD channels, although newer antennas may do a better job. Still, it may be worth trying out that old antenna before sending it to the trash heap.
If you do decide to take it down, make sure you don’t leave any holes in the roof. This may mean leaving part of the antenna or its mount attached, just so there’s nothing removed. If necessary, use a hacksaw or bolt cutters to take the antenna off the mount. It was probably bolted on but those bolts may have rusted by now.
When you have the antenna down you’ll find that you have 5 pounds of antenna, and it’s mostly aluminum. That may give you a recycle value of maybe three dollars. Heavier antennas will give you more, but there’s no way you’re getting rich from salvaging antennas unless you salvage a lot of them.