fanhui
Fanhui refers to the modern Chinese practice of sending one's spent matches or cigarette butts back to the producers after they have been used. This practice is often performed as a means of customer feedback, allowing producers to assess the quality of their products and make changes accordingly.
The practice of fanhui is believed to have originated in the early 2000s, when Chinese cigarette manufacturers
Fanhui is typically performed through designated channels, with some cigarette manufacturers, particularly those with internet-based platforms,
Some Chinese researchers have used fanhui to analyze the chemical composition of returning matches, as well