Conservation of banknotes refers to any form of restoration, pressing, alteration, or modification that is performed for the purpose of improving the overall appearance of a banknote or enhancing the integrity of the paper. Conservation of banknotes is frequently frowned upon and is a controversial subject. This tendency is understandable in many cases — some banknotes are restored for the sole purpose of deceiving others, while others are restored unprofessionally, resulting in further damage to rare pieces. I am of the view that these decisions should be handled case-by-case.
For example, I have purchased very rare pieces which were already repaired, albeit very crudely. In such cases, I believe that there is no reason I shouldn’t undo the crudely done repair and redo it with the help of a professional conservator. Other pieces that found their way to my collection are damaged examples of moderately rare banknotes. A piece in VG could cost a small fraction of what a VF would cost, sometimes making the purchase of a VF prohibitively expensive. In such cases, I see no harm in restoring some of the attractiveness of an undamaged note.
One thing remains unchanged in spite of all of the above: any restoration or alteration performed on a banknote must always be disclosed without any exceptions. Any deviations from that are considered to be unethical.
Below is an example of a Palestine 1 Pound dated 1927, the most difficult of all 1 Pound notes. An original VF example could cost over $4.000. This one was purchased at a fraction of this price, and with minimal restoration work it now looks like a F, possibly a low-end VF. My intent was not to make it look “new” but rather make it “easy on the eyes”.