[VitacoreVision]

You have Civil War money? That's impressive.

Greenback (1860s money)
https://en.wikipedia.org/wiki/Greenback_(1860s_money)

Greenbacks were paper currency (printed in green on the back) issued by the United States during the American Civil War.

[Ruy Dias de Bivar]

Modern paper money is considered greenbacks. The Kingston Trio did a song about them.

And I don’t give a damn about a greenback dollar
Spend it fast as I can
For a wailin’ song and a good guitar
The only things that I understand, poor boy
The only things that I understand