Did you know that some silver certificates had yellow seals? I bet you've never seen them before.
You think of World War II as mainly a European War but did you know that the Allies fought against the Vichy French in North Africa. This operation, Operation Torch, commenced on November 8, 1942. The success of it was a major turning point in the War, removing Axis control over North African oil reserves, and providing the Allies with a base of operations to retake southern Europe.
The U.S. soldiers who fought in North Africa were paid in cash. The leaders were worried that the enemy could capture their payroll and use that money against them. The solution they came up with was to create a set of distinct set of notes, nicknamed "North Africa notes". All military personnel serving in North African were paid with these special silver certificates, which had a unique yellow seal. Now if the money fell into enemies hands they could refuse to honor them which would render them useless.
Unlike the “Hawaii” notes, which were made for circulation among the general population, North Africa notes were distributed only to military personnel.