It’s very rare that I can pick up a piece of litter and know exactly
where it came from and who dropped it. The exception is rubber bands. These can be found
along most residential streets, and are dropped by posties as they go about their
business of delivering mail. This phenomenon even has its own Wikipedia
page–although the bands are no longer red–and the number of rubber
bands that the Royal Mail goes through each year is truly staggering:
https://en.wikipedia.org/wiki/Royal_Mail_rubber_band