I used to cut scrap metal for a farmer. I had this big acetylene torch, and I would go around the farm, cutting up antiquated and rusted farm equipment and loading it onto a trailer. The farm was old and huge, and we'd pull a few tons of metal out of there every week. The farmer sold this metal for scrap, and he made enough money to pay me and still profit off his treasure trove of metal.
Not all of us are going to own a farm full of metal equipment from the Depression Era. That's a rural thing, but anyone who has a garage, shed, basement or backyard will probably have some extra metal taking up space.
This metal can be sold. It's in high demand right now. The price is only a few cents per pound, depending on the metal. Some metals are worth about a quarter a pound. It doesn't take much metal to make it worth your while. In Los Angeles there are plenty of people who pick through dumpsters for aluminum cans, but iron, steel and copper is where the real money is at.
In some areas they allow you to go to the dump and pull out anything you want. This is another way to make money off scrap metal. Make sure to wear gloves and update your tetanus shot. Many metal merchants have recently started accepting old appliances. This wasn't allowed in the past. There are probably junkyards full of fridges and stoves that are ripe for the plucking.
Recycling metal is a good way to make extra cash. Some people even do it for a living. You don't have to start a lifestyle of salvage, but you should recycle the wasted metal in your own home.