Originally posted by scientist
that is a stamp from a special kind of pen that will tell if the bill is counterfeit or not.
Originally posted by KitKat81
Dont want to scan the entire thing because isn't against the law?
Originally posted by Dorian Soran
That looks like a "marker" stamp that was placed on the bill AFTER it was printed at the mint.
Marker stamps are used by financial institutions, casinos, walmart, etc to mark bills as they are counted. This was/is done by places that do not have the ability to use electronic bill counters and will stamp every 50th bill or so.
Originally posted by yuefo
I have a 1996 and 2001. Neither has an inverted pentagram, and I didn't expect them to. There ARE some oddities about our currency, but this is someone hoaxing around. I'm not accusing the OP, just someone.