William Connolley notes that in some cases, the containers are shipped back to China full of trash:

“China is buying up everything it can. It is sucking in material from all over the world and it doesn’t give two noodles what it takes,” said one plastics recycler who asked not to be identified. “I know of 300 firms, mostly in China, offering to buy my plastics. I have three or four companies cold-calling me every day from China requesting material. They have very cheap labour to sort the material but the shame is that it is being done there and not here. They don’t care about the quality, or the contamination. No one checks what is sent or what arrives.”