The OSS re-created all aspects of the German Postal system from real business return addresses to many thousands of names and addresses pulled from the telephone directories.  They even replicated the mail bags, postal markings and every other detail of the postal system.  Every letter was franked with the fake "Skull" stamps.  On opening the letter, they would find it filled with anti-Nazi propaganda often including the 12pf red "Futsches Reich" stamp.

"War is Hell" as we all know, and Donovan wrote to Roosevelt: "Every fortnight approximately 500 to 1200 copies of the Frankfurter Zeitung are likewise sent into Germany where they are mailed to individuals whose addresses appear in the death notices of soldiers who are reported to have died for the fatherland."

The original forgeries are fully catalogued in Michel, and of course are rare and expensive and seldom are offered on the market.  A huge amount of detailed info on this amazing propaganda campaign, and the Hitler forgeries and reprints can be found here:

http://www.psywarrior.com/Cornflakes2.html

I bought these mint reprint/forgery Miniature Sheets of 4 stamps over 25 years ago in my first year of stamp dealing, from an old dealer of Jewish background,  and have not seen them since until cleaning up this month!   I have no idea of their origin, but they are obviously well over 25 years old.  

 

Surely be a useful sideline addition for Judiaca or Germany or USA or forgery collectors?  One x  fresh imperforate MUH Miniature sheet exactly as shown in photo $A30 (very approx $US 22) or per 5 -  $A90