For those engaged in literature drops, I am sure we're all in agreement that none of us want to run afoul of the federal mail regulations with respect to federal mailboxes that people have on their homes or in front of their addresses.
Some of these points might seem obvious and others may not but I am putting them here to avoid issues on anyone’s part.
-- Handouts and other lit drops cannot be placed inside a mailbox.
-- It cannot be otherwise attached (e.g. taped) to the mailbox.
-- You cannot hang the literature on the door opening hook or behind the flag or over the flag.
What is permitted:
If the mailbox has a gap under it or behind it (e.g. wood beam on which it sits) you can slide your literature under it or behind it but doing so must be done “without touch”; this means the act of taking the literature and simply sliding it under or behind alone – if you have to use your free hand in any way to get it to stay then it’s an unpermitted use. (Basically you cannot touch the mailbox).
If there is a newspaper tube you can place the handout / literature inside of it.
On house mounted mailboxes that have underhooks for newspapers, you are permitted to use these.
If there are any questions the Wallingford Postmaster is more than happy to address questions or concerns.
Here is the additional information I looked up in the meantime from the USPS website regarding customer mail receptacles.
Other than as permitted by 3.2.10, Delivery of Unstamped Newspapers, or 3.2.11, no part of a mail receptacle may be used to deliver any matter not bearing postage, including items or matter placed upon, supported by, attached to, hung from, or inserted into a mail receptacle. Any mailable matter not bearing postage and found as described above is subject to the same postage as would be paid if it were carried by mail.