My DH is obsessive about collecting cans, he even goes ditch-diving during the nicer months. Collects them from work, all that fun stuff. He hangs onto them until the price of aluminum goes high, then turns them in. The price has to be right because the scrap yard he goes to is about 20 miles away (at one point the price was almost 90 cents a pound, now it's down to 46 cents a pound so he's hanging onto them for now). We've got about 90 pounds of cans in our basement now. 26 pop cans make a pound, and I think 32(?) beer cans make a pound. He recruits our 4-year-old to help him crush them when he gets a bunch stored up.