After arriving to China I found it interesting that whenever I went over to a Chinese friends home they would always ask me to take off my shoes and put on sandals. I thought this was a bit bizarre at first and asked a Chinese friend why this was the case, she said "Well, it's simple really. Outside the ground is a dirty place. Why bring that dirt into your home." I realized "outside" is a dirty place, but in the States we are still okay from time to time to walk in the house with shoes on. My friends comment made more sense however, after I saw how Chinese people will treat the public walkways - as makeshift restrooms, where kids can pee on curbside and public buses, and even grown men can let one fly in the metro stations. It's true, and I've seen it on more than one occasion.
Moral of the story. I now have a very nice pair of sandals by the my door.
There's probably some things you would not mind taking second hand- bikes, iPods, jackets, maybe even jewelry. One thing you'd likely not wish for second hand, however, is something that in China you're offered very often- cooking oil.
In China there's something called "Dee-go-yo" which literally translates as "second-hand oil". This isn't something we're exposed to in the west as oil is cheap and the idea of reusing it is disgusting. But in China, if you go to a more local joint- a smaller, cheaper restaurant, it's very possible that fine cuisine is covered in it.
So why use second hand oil? In China restaurants look for ways to save money, so what happens is they will throw out the oil, or it's drained into a large vat, which looks much as a sewer. Later on, usually about once a month a van will come by in the late evenings with large 20 gallon plastic tubs and workers will scoop the solidified oil into the buckets and drive it back to some unknown location where they take the oil and "purify" it by heating it up, removing the impurities, and then re-bottling it and selling it back to the original restaurants at a discount price.
Oddly enough, second hand oil can actually taste better (like that frying pan your grandpa never washes), but packed away in that oil you discover loads of toxins. Hmmm, yeah. It's not just the MSG that makes Chinese food taste so good.