Delivering leaflets can present occasional hazards. The stiff bristles in letterboxes can scrape the skin off your knuckles, your fingers could become prey to dogs or the leaflet just crumbles on insertion, to name a few. I have tried the scissor tongs shown here LINK EDITED OUT BY MNHQ and it seems ideal. It is thin enough and long enough to go through every letterbox I have tried, and, as the photo shows, is an ideal size for leaflets. Usually you can simply slot in the leaflet, insert in the letterbox, open slightly and withdraw. The letterbox brushes tend to stop the leaflet being pulled back out. Alternatively once fully inserted rotate 90 degrees, open slightly so the leaflet falls out, close, rotate back and withdraw.
If you try this make sure it is a thin scissor tongs so it cannot get stuck
in or damage a letterbox.
As a bonus it also speeds up delivery.