Hi All,
May be this will help, Germany had used money called Notgeld meaning emergency money in the past. It was mainly used during the times of war and crisis. Example: When a town was besieged it was cut of the money supply and frequently invented some money to be used inside the town.
Maybe your coins are something of this sort
Here is note issued by Fried Krupp in 31st December 1923.
Alf.