Hamm issued zinc notgeld in 1917 under the same wartime pressures that pushed hundreds of German municipalities into emergency coinage — copper and nickel had been requisitioned for the war effort, and the Reichsbank could not fill the gap in small change. Zinc was the compromise material, cheap and available but prone to corrosion, which accounts for the surface degradation seen on most survivors.
Hamm issued zinc notgeld in 1917 under the same wartime pressures that pushed hundreds of German municipalities into emergency coinage — copper and nickel had been requisitioned for the war effort, and the Reichsbank could not fill the gap in small change. Zinc was the compromise material, cheap and available but prone to corrosion, which accounts for the surface degradation seen on most survivors.