On February 5, 1945, with World War II in its last desperate months, a German train made its way to the city of Linz. Suddenly, Allied planes swooped in, dropping bombs and derailing it. As the train’s cargo—mail bound for several northern Austrian towns—scattered over the area, a second wave of bombers flew in with a strange payload.
Eight mail bags hit the ground around the train with a thud. Inside each bag were 800 propaganda letters, all addressed to homes and businesses along the train’s route and appropriately stamped. When the train was discovered, German postal workers recovered the bags and delivered the letters without being any wiser about their contents or origins.
Operation Cornflakes had begun.
Propaganda was a favorite tool of the Office of Strategic Services during the war, but the usual method of distributing it, airdropped leaflets, had major drawbacks. Huge numbers of leaflets had to be produced to increase the chances that those who were supposed to see them actually would. Even with enough materials, heavy winds, rain, or Nazi knowledge of a planned drop could result in diversion or destruction of the leaflets before they reached their audience. There had to be a way to remove the variables and the risk from the operation and hand the propaganda right to the Germans.
Eventually, they hit upon the idea of using the German postal service itself as a distribution system. They’d make their materials look like legitimate German mail, leave it around bombed trains, and let the enemy collect and deliver it. The German government would wind up bringing the Allies' propaganda right to its own citizens every day. What’s more, the plan had the added benefit of straining the already overworked and chaotic German communications and transportation sectors.
Operation Cornflakes (named so because the subversive mail was usually delivered just as its targets sat down for breakfast) had many advantages over simple airdrops, but required a lot of legwork to get off the ground. The inner workings of the German mail system had to be learned, so POWs who had been postal workers were interrogated about everything from postal cancellation markings to the ways mail bags were supposed to be packed and sealed. Spies and sympathizers gathered samples of stamps, postal cancellations, mail sacks, and envelopes while OSS staff pulled names and addresses from German telephone directories.
Every aspect of the German postal system, down to the smallest details, were replicated, with some small changes. While most of the envelopes were franked with a regular stamp, some went out bearing subliminal insults. Forgers manipulated the standard stamp with Adolf Hitler’s face to show the Fuhrer’s exposed skull. Other stamps had their country tag on the bottom changed from “Deutsches Reich” (German Empire) to “Futsches Reich” (Ruined Empire). Update added : 3/6/12 - Some featured both changes. These subliminally insulting stamps were stuffed inside the envelopes with other propaganda and, in some cases, maybe even used as postage on the letters (This latter use isn't as well documented as the former. See discussion in the comments below).
Once they knew the ins and outs, OSS operatives scattered throughout Europe began preparing materials. A group in Rome prepared envelopes with more than two million names and addresses at a rate of 15,000 envelopes a week. Groups in Switzerland and England, meanwhile, printed propaganda newspapers and letters and forged stamps. Swiss neutrality posed a serious problem for the OSS office there. With the German Army on its border, Switzerland did not want to face retribution for unwittingly hosting Allied agents, so the government constantly tried to track down and deport operatives there.
When all the materials were prepared, the loaded mailbags were turned over to the 15th Army Air Force, which was tasked with delivery. Special bombs were designed to hold the bags and were equipped with a detonator linked to a control in the cockpit. With the push of a button, the pilots could launch the mailbags at a height that wouldn’t damage them, and then keep the bomb canister on the plane to prevent the Germans from finding evidence of the drop.
Most of the fake mail bore return addresses for legitimate businesses, like the Wiener Giro-und Kassenverein, a central securities deposit. This address eventually blew the operation’s cover when an OSS operative writing out the addresses misspelled the name as “Cassenverein.” After German police recovered Allied mailbags from one of the train bombings and took it to a post office, one of the postal clerks noticed the misspelling. The same mistake turned up on several envelopes and the postal workers grew suspicious. They opened the envelopes and discovered the propaganda. Operation Cornflakes was shut down because of a typo.
Over the course of the operation, 20 loads of fake mail were dropped for a total of 320 mailbags and more than 96,000 pieces of propaganda mail. For all the mail that made it into German homes, though, no one is sure if Cornflakes had any significant effect, at least psychologically. The Allies attempted to evaluate the damage their psyops did to enemy morale by surveying German deserters and POWs, but the results were murky. At least 10,000 of the men questioned said they were directly affected by OSS propaganda at some point during the war. For the rest of the soldiers, demoralization was cumulative and affected not just by propaganda, but injuries, battle fatigue, deaths of fellow soldiers, and other conditions, and Cornflakes’ effects just couldn’t be pinpointed. From a strategic standpoint, however, Cornflakes was a clear success, putting extra work on the German postal system and delaying mail, and forcing the German government to divert resources to repairing damaged trains and rail routes.
Most of the forged stamps, envelopes and their contents were destroyed during war, either by the post office after the fraud was discovered or by the mail’s recipients, who simply threw it away. A few items did survive, though, and are highly valued collectors items. To please the keepers of the purse strings, the OSS collected some of the propaganda material and forgeries it had created and compiled them into booklets to gift to members of the Congressional Oversight Committee. Several of these scrapbooks made it out to the public and have sold for as high as $5000. A number of forged German stamps entered the public marketplace when President Franklin Roosevelt’s stamp collection was sold at auction after his death and continue to circulate. Many of these items, especially the Hitler skull stamps, are so sought after by collectors that some people have started to produce and sell forgeries of the forgeries.