Rare D-Mark: These old coins can still be very valuable. Made of silver, copper or because of their special embossing: some D-Marks are really valuable.
Not every coin is worth a lot; you should pay attention to special, commemorative and incorrect mintings. Some 5 and 10 mark coins contain 10 grams of silver. The current value of these coins is also higher than the original one. But be careful, melting the coins is not always worth it due to the material.