Ok, so I search through US Currency Notes also and keep the cool stuff. Here's a $1 Note that immediately caught my eye. A keeper?
Because the color and bleed match so well, I'd say it is possibly excess ink on the prefix wheel that got on the note. Wet a Q-tip with acetone and rub it to see if it bleeds. If it does, then someone used a marker on it. The ink on the note will not be affected by the acetone.
And I agree.... good eye Sal new glass's? As the ink is a different color...and the line has a slight curve..and the line has bleeding so ink after the fact....
Nice minor error and one that you don’t see very often. It’s extra ink on the wheel that spins the numbers. In this case, the letters. Definitely a keeper.
The line is a bit wobbly, and is a shade or two more blue than the serial number ink. Graffiti, not an error.