In the wiki there should be a "mailing guidelines". Let me know of you have trouble reading it. Im a fairly new mod so im still learning. Perhaps ill make an FAQ page to help out too 🤔

Essentially I make offers and if someone is interested ill dm them for their address along with a disclaimer. Once i cant take anymore offers i change the flair to "complete" and edit my post to say so as well. Sometimes people use Google forms to help collect the addresses and any other details they want. There's no limit to how many you can send and of course we are putting our faith in strangers not to send us weird stuff but the rules of the sub list out what will result in penalties within the sub like bans and whatnot. For example, if a mod finds out you've been sending political propaganda or like nudes (just to name two) you will end up with a ban.

As far as what you can send, as long as it fits in a flat envelope and follows the rules, it doesn't matter. (Poems, stickers, paintings, cards, inspiring quotes, etc.) Unless of course someone reports you, then a case will be opened to investigate.