Yes, if you know what you're doing, scrap metal is absoltely worth it. Trash night is popular around here with people driving around looking for people like you who are just throwing out one or two pieces, like a bed frame, etc. For ferrous metal (a magnet is your friend here) the rate here is $11.62/cwt (hundred pounds) so that bed frame, bikes, refridgerators, appliances, etc, can add up quick. Depending on if you're in an area with a deposit on your soda cans, aluminum is also a popular scrap metal item. Here people throw out their cans in the recycling bins, since there's no deposit. cans are worth .62/lb currently. There's a local guy that drives a golf cart around and collects the aluminum cans every trash night. Then of course there's copper, brass, computer scrap, electrical motors, etc. Anything that has an electrical cord has copper wire in the cord. If you're throwing out an old toaster, cut the cord off. Most scrap metal places will buy a collection of cords off you at the aluminum price, but if you strip off the insulation so you have bare copper wire, then it's usually another .90/lb above that. (do not burn the insulation off...it's a hazard, and will change the color of the copper. One scrap yard I've dealt with won't buy it if it's burned)
anyway, like emptying a storage unit, there's a lot of work in scrap, but there is some money to be made.
Not long ago I bought a 10x15 unit that was full of scrap metal (along with plenty of other stuff): chain link fence, old lawn mowers, bikes, etc. Paid $200 for the unit, made a few trips to the scrap yard and made $260 in scrap. Then I had all the non metal stuff to sell for profit.