Germany had something a bit similar. The two Pfennig coins made before 1968 were pure bronze and worth more than two Pfennig as scrap metal in later years. But it would be illegal to melt them down. And they were abolished, of course, when Germany switched to the Euro at the end of 2001. If you found a hoard of them now, would it be legal to melt them down?
(Apparently there was an official exception to the law against destroying currency. Those coin-operated machines that squash a small coin and stamp a picture on it for tourists, apparently they were officially legal, rather than just allowed because "we're not going to bother enforcing the law in this case" as they would be in most countries, I guess.)