Re: 1940s methods of spotting counterfeit bills?

Enio,

You are assuming that the US detected the counterfeits.  Tee hee...
I couldn't find much information about the Nazi's counterfeiting US 
currency, but there apparently was a lot of counterfeiting going on.  
The US entered the war late (December 1941, about 2 years into the 
war).  Probably before this the Nazi's wouldn't have wanted top 
counterfeit US money because good trade relationships with the US were 
more important than money.  Us troops found conterfeit US currency and 
presses when they captured concentration camps, but I couldn't find any 
examples of the US recognizing counterfeit money in the US.  It is 
possible that the Nazis started counterfeiting late in the war and 
didn't actually pass any of the fake US money.

I talked to some retirees who would have had their first jobs in the 
late 1940's/early 50's about how they would have spotted counterfeit 
money.  A typical responce was that fake money back then looked like it 
had been "drawn with a crayon"  I doubt that the Nazi's counterfeits 
had this problem, especially if they were seeking out the best printers 
in Germany to make the counterfeits.

In the case of Nazis counterfeiting British currency, real British 
currency had slightly offset the line in the bottom N in "England".  
The Nazis corrected this, so this was how the two could be 
distinguished.  Counterfeits being too perfect is a possible way of 
recognizing fake money.  (Although the British weren't so good about 
spotting the fakes.  By the end of the war one estimate was that 40% of 
British 5 pound notes were fakes.)  During the War Between the States 
the Confederacy spotted counterfeits made by the Union because the fake 
bills were better in terms of paper and printing quality.  During WWII 
the British had divisions of people whose job was to crumple and 
uncrumple and generally to handle foreign money that would be issued to 
spies.  (Well not just money.  They were aging suitcases clothes and 
anything else that would be issued to spies.)  Presumably Nazis had 
been suspicious when spies used all new bills to pay for things.  Aging 
goods for use by spies was a side story in Between Silk and Cyanide, a 
good read about spy stuff by Leo Marks.  Certainly aging the money 
would have been a problem if the Nazis were making large quantities.

As I said I couldn't find any examples of this fake currency being 
spotted, so I don't know how the US would have recognized it even if it 
had know to look.

-Wilhelmina Randtke

More information on counterfeiting:
 http://www.treas.gov/usss/know_your_money.shtml
The US treasury's website on counterfeit US currency.  They don't have 
information about the Nazi's but they do have a good mix of historical 
information on counterfeiting and on counterfeiting today.
 http://currency_den.tripod.com/War_Counterfeits/war.html
A lot of information on counterfeit currency made specifically for use 
in wars.  There is a section on Nazi counterfeit operations, which was 
a major source for the above answer to your question.