Does anyone know postal...uh... Rules? Like, what if I wanted to mail a dead leaf. Can I mail leaf? :I
You said
A dead leaf? As in,
one? Sans envelope, a la postcard?
This is a modern letter sorting machine. If someone were to feed a
dry leaf into it, I'ld expect it to come out the sides.
Several sides. Sides even the machine's designer is not yet aware of.
Other than the stability aspect, novelty and downright make-belief "postcards" aren't unheard of. DIN size (A6 ~= 10.5 x 15 cm), ITU size (9 x 14 cm), oversized, beer coaster, whatever.
Whether your postcard - or, for that matter, overseas container - will be rejected
because it's a leaf is up to the recipient nation's customs office, so there's no global guideline to give. As far as Europe is concerned, I doubt that dead leaves would raise a red flag. We brought our share of neophytes to our countries
ourselves in centuries past.