Invisible ink? No, just a polymer note and an eraser
- Published: Nov 6, 2016, 3 AM

Multiple Scottish media reports inform that not only can polymer notes be baked and fried to shrink them, but the ink on them can also be erased to the extent that they are nearly unrecognizable. The discovery was made by a print center manager named Stuart McLean, who decided to experiment on a new Clydesdale Bank £5 note with a pencil eraser. He learned that he could remove large parts of the note’s ink, leaving only serial numbers and the see-through hologram.
Connect with Coin World:
Sign up for our free eNewsletter
Like us on Facebook
Follow us on Twitter
McLean told the Scotland Herald in an interview: “I had a bit of down time at work and we were talking about the new note, and I happened to have one on me so I got it out and noticed it had a dirty mark. I used a pencil eraser to rub it out and I found that the ink underneath rubbed away as well. I kept on going and was able to turn one side completely white.” He then disclosed that he tried the same thing on a Bank of England polymer £5 note with similar results.
The story of McLean’s exploits broke the same week De La Rue, the manufacturer of the “Safeguard” polymer substrate used for the note, issued a news release lauding its success with the material. Oct. 27 was the date of issue for the 21st note — coincidentally a Royal Bank of Scotland £5 note — to use the “Safeguard” polymer.
As for the erasing, a De La Rue spokesperson said that, under normal use, notes do not lose their ink and this was a case of excessive and abnormal activity. Furthermore, “Whilst ink wear is the ultimate failure mode of polymer banknotes in circulation, the ink wear displayed here appears to us to have been achieved by a method not representative of what happens to a banknote under normal circulation conditions.”
All three Scottish £5 notes (Clydesdale Bank, Bank of Scotland, and Royal Bank of Scotland), along with the English “fiver,” are now printed on the same polymer material.
MORE RELATED ARTICLES