Although post-it notes have a low-tack adhesive and are designed to be removed without leaving a mark, over time the adhesive hardens. I removed a post-it note (1990 vintage) from a Christmas card Carl Giles had illustrated and it left a ‘gunge’. Luckily it was one of many duplicates but what if it had been the only copy or highly valuable? One option would have been to leave the post-it note attached and let the adhesive degrade over a longer period of time so that it would eventually dry out, allowing the post-it note to fall off. But it would still leave a stain. The same thing applies to sellotape, so remember that when you are taping torn pieces of paper back together. […]
As post-it notes are a relatively new invention they are going to be found in greater quantities when material from the 1970s onwards get appraised to see if it is of archival value and needs to be kept. So, keep this in mind the next time you want to use our multi-coloured ‘friend’.
I wonder when the oldest post-it note still attached to a document was first used?