I didn't include images because for most people if you've seen one $1 FRN, you've seen them all. I'm working on 1963 and 1969 series $1 small-size notes sets. Just got: -- a $1 US a 1969-B Dallas star note (K/* block) -- a $1 US a 1963 Minneapolis star/mule note (I/* block) -- a $1 US a 1969-B New York note (B/B block) -- a $1 US a 1969-B New York 5-note serial number sequence (B/B block) I don't think there are many people who collect US currency that way, but since I'm well into it I can't stop now.
I think it would make an interesting and educational collection. Some photos would be nice to look at. A star/mule ?
Obviously it didn't occur to me that the term "Mule" might be new to some people. So I'll explain. "$1 Federal Reserve Note mules are notes whose back plate numbers appear in consecutive series." The note shown is a Series 1963 $1 Federal Reserve Note (FRN) as shown by the imprint "SERIES/1963" on the front. It was distributed from the Minneapolis Federal Reserve Bank as indicated by: -- the four number 9's on the front, and -- the name MINNEAPOLIS/MINNESOTA and the letter "I" in the black seal on the front, and -- the serial number beginning with the letter "I". It is a replacement note as indicated by the 5-pointed star with the open center at the end of the serial number. That covers the obvious and commonly known features on the note. MULES Mules are notes whose back plate numbers (on reverse side of the notes) appear in consecutive series. In this case the back plate number is 444 (look at the lower right of the center open area). That back plate was used during the printing of both the Series 1957-B $1 Silver Certificate(!) notes and the 1963 Federal Reserve Notes. The hard part is knowing what back plates were used for both series. Of course you can access that information from US Government records through the use of the Freedom of Information Act. Or you can find it listed in a publication created by someone who did all that work for you. The only such source that I know of is Collector's Guide to Modern Federal Reserve Notes/Series 1963-2009 by Robert Azpiazu, 2011. It's out of print and there is no newer edition. You'd be lucky to find the guide even in used condition.
The above explanation can be confusing. A Mule is basically a note with a back plate that was used in a previous series. Many of 1963 $1 FRNs were printed with back plates originally used on 1957B $1 Silver Certificates.
