Here's an even easier way to detect what under the Constitution is "counterfeit" - if it says on the bill "United States Note" it is legal currency, backed by the wealth of the United States, worth one dollar of Gold and Constitutionally sound.
If it says "Federal Reserve Note" than it is worthless and not backed or supported by anything and currently worth around 0.000002 cents worth of Gold; Constitutionally counterfeit according to Section 8, Article 5 and subject to Congressional Constitutional demands to arrest the counterfeiters and seize the counterfeit currency.
No need for any special techniques to tell if it is phony money…just look at the label the globalist propaganda scum put on <<<their>>money.
Symbolism will be their downfall BUT ONLY if those symbols are understood and then eliminated.
United States Note=REAL American currency.
Federal Reserve Note=Counterfeit currency, worthless and used as slave-script.
#WWG1WGA
#NOTONEDEMOCRAT2020!
#NOTONESOCIALIST2020!
#NOTONERINO2020!