I just spotted this story on the KVOA News 4 Tucson website:
Help fight hunger by leaving food donations at mailbox Saturday
It's going to be hot today, and I've read stories of peoples' cans of food bursting when they get really hot. So if your letter carrier comes later in the day, you might want to wait until closer to that time to leave your donations. Or stop by a post office.
(In other mailbox news: I'm slowly gathering more photos. I hope to post a batch fairly soon!)