 Copper prices began to rise in 1973, to such an extent that the intrinsic value of the coin approached a cent, and citizens began to hoard cents, hoping to realize a profit. The Mint decided to switch to an aluminum cent. Over a million and a half such pieces were struck in the second half of 1973, though they were dated 1974. At congressional hearings, representatives of the vending machine industry testified that aluminum cents would jam their equipment, and the Mint backed away from its proposal. Mint director Mary Brooks sought the return of samples which had been distributed to members of Congress, but 14 remained missing, with the recipients affecting not to know what had become of them. One aluminum cent was donated to the Smithsonian Institution for the National Numismatic Collection; another was reportedly found by a US Capitol Police Officer.
