We had just enough time after returning to the hotel after lunch to walk to the nearest office of China Post. (Laura and Camila--hope you get your postcards soon. UPDATE: One postcard arrived 10/25 and one arrived 10/26.)
Whenever we go out, we see large bundles being carried by various means. Only once have I been able to see what was in one of these bundles, and it was recyclable plastic. There is no formal recycling system, but people will collect recyclable materials to sell.