It is annoying if you tear a banknote you plan to spend, but damage such as tears, creases and marks badly affects the value of older notes traded by collectors. According to The International Bank Note Society, the use of paper money---in the form of a trading receipt---dates back to Roman times, while the oldest-surviving banknote was issued around A.D. 1165 by the Chinese Emperor Hiao Tsung. Even the smallest defects, such as minor folds or creased corners, can reduce the "grading" or value of a note to a collector. Mending a damaged banknote may not increase its worth, but badly mending one will certainly reduce its value.
Put a little alcohol onto a soft cloth and gently rub this over the ink or stain.
Float the banknote in a bowl of clean water to remove the alcohol and as much of the ink or staining as can be lifted from the note's surface.
Dry the banknote by laying it between sheets of paper and then pressing the sheets flat between the leaves of a book.
Gently flatten a crumpled note by pressing it with your fingers.
Unfold bent corners gently using your fingers.
Place the crumpled note inside a clear plastic folder. Clear plastic is useful to check that the note is lying flat and that you are not about to accidentally introduce more creases or dog-eared corners.
Place the folder between two books to flatten out the note.
Use clear sticky tape to repair a torn banknote only if it is standard currency you plan to spend, rather than a more exotic banknote you wish to collect. Lay the pieces of the note together on a flat, non-porous surface, such as a plastic tray. Make sure the fragments all have the correct side facing up. Join the pieces with a length of clear sticky tape.
Press the tape flat with your fingers, working from one end to the other, to avoid introducing rucks or creases. Cut off the ends of the tape neatly, using scissors. Turn the note over and tape the facing side in the same way.
Send a current banknote that has been taped together to the U.S. Treasury's mutilated currency division, The Bureau of Engraving and Printing, if your mended note is refused in a shop or bank. Include a letter explaining how the note became damaged, along with your contact details. According to a CBC News report, it can take between two days and three weeks for the division to establish whether or not the note is valid currency. The Bureau's website adds that where processing takes more than eight weeks, a written receipt will be issued. If the Bureau finds in your favour, it will send a check for the value of the bill or bills you have submitted. In 2009, £29 million U.S. was recovered in this way.
Mail damaged, current banknotes to: Bureau of Engraving and Printing, MCD/OFM, BEPA, Room 344A, P.O. Box 37048, Washington, D. C. 20013. Send your notes by registered mail and request return receipt. If the value of the bills you are mailing is substantial, consider insuring your package.
Place a torn---but collectable---banknote into a clear plastic folder that will display it without the need for sticky tape. Collectable banknotes should never be repaired with tape, according to the collectors' website Banknotes.com, as the adhesive chemicals will degrade the note, markedly reduce its value, and perhaps leave it worthless.
Try repairs only on banknotes that you do not highly value. Only expert paper conservators should repair very valuable banknotes. If in doubt, refrain from repairing a note until you have checked its value. Do not iron a note to remove creases. This is likely to be unsuccessful, according to the collectors' website, Banknotes.com, and will almost certainly reduce your note's "grading," or value to other collectors. Folds or creases should be seen as part of that particular banknote's history.