Very informative however I was pondering on the use of the term flaps and not letterbox as would be the normal custom in the UK .Unlikely to be the US for a couple reasons:
1. “Postman” is more of a historic term used here, they are more usually the “mailman”, or officially, “mail carrier”.
2. Most US mailboxes are at the side of the road, not a flap in a door.
In most urban areas, they have dedicated, purpose-designed vehicles like this, which are right-hand drive, so the mailman just has to reach out to the mailbox from the driver’s seat:
View attachment 604287
But in more rural areas (like my area) they can/do use private vehicles. Thus there is a market for things like right-hand drive Jeeps. Seems odd seeing one with the steering wheel not there on the left, but then they have “USPS” stickers on them and all becomes clear.
So the “clean flaps“ is probably not in the US, sorry.
So I blamed the Yanks as everybody nose they are a strange lot