Most broken banknotes were one-sided with plain reverses such as the reverse of the following R-7 plate note from the book: Obsolete Notes And Scrip of Rhode Island and The Providence Plantations by: Roger H. Durand (1981). When notes exhibited overprints of different colors, they sometimes soaked through and are visible on the reverse.
$5 Bank Of The South County of South Kingstown, RI (1855)
Reverse Of Plate Note of Durand 1260 found on page 211
Because most notes were printed on one side only, if not all the notes printed were issued, the uncut sheets would have other notes printed on the other side and issued. They would generally be printed on the reverse and at a 90 degree angle to the prior printing as seen in the following $1 reverse of the Bank Of Augusta, Georgia.
$1 Bank Of Augusta, GA (Remainder)
The reverse of the above $1 Bank Of Augusta note has fractional notes from the same bank as shown above. This feature is not only characteristic of broken banknotes. Some Southern States issues from the Civil War era also "recycled" paper. The following is the reverse of an 1862 North Carolina 50 cent note priinted on the back of a NC bond. The $40 bond coupons on the reverse are seen below.
50 cents State Of NC (1862)
Some notes had the names of the stockholders on the reverse. I figure that this gave one confidence in accepting the note if they knew who the people that ran the institution are. One example is the following $1 note from the Dubuque Central Improvement Company of Dubuque, Iowa (1858).
$1 The Dubuque Central Improvement Company, Dubuque, IA (1858)
At times, a list of handwritten signatures can be found on the reverse of some notes. There were many counterfeits made to the Waubeek Bank of De Soto, Nebraska (1857). To insure that one was receiving a genuine note, the person spending the note would sign the reverse. This allowed one to trace it back to the original spender in case the note was indeed a counterfeit. The following reverse is from an authentic $5 note from the Waubeek Bank.
$5 Waubeek Bank, De Soto, NE (1857)
At times, a banknote would have a beautiful vignette on the reverse such as the following from a $5 note from the Bank Of East Tennessee.
$5 The Bank Of East Tennessee, Knoxville, branch at Jonesboro, TN (1855)
Notes that have reverses sometimes don't get their reverses perfectly centered. While slightly askew reverses can be readily available on 1861 NC one dollar notes, being drastically off centered, such as the note below, is quite rare of an error. The one dollar is supposed to be perfectly centered on the reverse.
$1 State Of North Carolina Error Note (1861)