HDDs are manufactured differently and have different components per unit. So, not all of them have the same aluminum content. The parts that are surely aluminum are the stack of shiny platters and sometimes the inner casing of the HDD.
What you need to do is to disassemble the hard disk by removing all of the screws in its primary case. Some screws are under the stickers so you’ll have to feel for the indents on the sticker. After locating all of the screws, just pierce the stickers and remove the screws underneath.
Cash-in on the aluminum – as mentioned earlier, aluminum can be sold at material recovery facilities. As a fact, a single hard drive uses more than a pound of aluminum found in the hard metal magnetic disk which serves as protective casing for the stored magnetic data. Aluminum is sold by weight and a regular HDD can be quite heavy. However, there is no definite answer as to how much a material recovery company will pay for a pound of aluminum. There is the matter of classifying the aluminum as dirty which means it has other metals present in its composition or clean if what you have is plain aluminum.
Based on information gathered from forum sites, the price range for selling a pound of aluminum at recycling centers is from 25 cents to 90 cents and will also depend on your location. What is suggested is for you to canvass from different recycling centers in order to get the best deal.