Unloaded boxes are called empty boxes. In South China, especially Guangdong and Hong Kong, empty boxes are usually also called auspicious boxes, because in Cantonese, empty and ominous have the same pronunciation, which is unlucky, so in South China, they are not called empty boxes, but auspicious boxes. The so-called pick-up and return of heavy goods means picking up empty boxes, taking them to be loaded with goods, and then returning the loaded heavy boxes.