Some more info on counterfeit bills..
Have a fair amount of experience in this area as former U.S Secret Service agent
(USSS is primary investigative lead in this area as branch of U.S Treasury Dept)..
First off- yes sometimes banks do make mistakes in accepting counterfeit bills but if they are new/nearly new I am slightly more skeptical as they are run through machines for detection.
If the bills are pretty worn- more likely.
If he said that he received more than one counterfeit from bank I am even more skeptical. Odds of getting multiple counterfeits from bank in one small batch very unlikely….
Most commonly counterfeited bill is $20 because (as has been noted) $100 bill (while a higher potential profit margin) attracts way too much attention.
Easiest way to “field test” a bill to determine if it is genuine is to :
1) Look for red and blue cotton fibers in bill-
if genuine you can actually pull them out with tweezers. Only one paper company makes paper for the bills- Crane Paper Company in Massachusetts.
They produce a very “soft” paper for the bills which is why most counterfeit bills feel “slick” to the touch
2)If bill is in good condition- one should be able to scratch under the portrait (where the jacket is) and feel the black ridges. This is because the black ink is actually printed on top of the paper and the black ink is microscopically higher than the paper. Conversely, any green ink is pressed into the paper. If you can feel the ridges in the jacket with your fingernail most likely genuine.
I have only personally seen one counterfeit note that had that feature (came out of Hong Kong) where a master engraver was involved.
Anyone who tries to counterfeit a note without engravers (99.9999% of the counterfeiters) will
not be able to duplicate these ridges on the jacket.
3) Over the years there are several other security features that have been added to the currency to make it more difficult like; Microprinting, magnetic threads, holograms,colors,etc.
Finally, if you call up the San Diego Secret Service office they can tell you if it is a “new note” (which they will be very interested in because it means they have not located the source yet)or if it is an old note/floater which means they have located the source/made an arrest but there are still a few bills floating around.
They will ask you to read off the faceplate (Numbers in front and there is a small number in the back (backplate) as well as serial # and Federal Reserve city.
