Objects fall into three categories: transient things that lose value as they wear out, durable things thought to keep or gain value forever, and rubbish, which has no value at all. A transient thing can become durable, but only by first dropping into rubbish. A cheap woven picture that vanished from the market can later be rediscovered and sell for large sums.
Movement between the categories goes in a single direction: from transient, to rubbish, to durable. Nothing durable falls back into rubbish, and nothing skips the rubbish stage on its way to lasting value. At the end of the line, a thing can leave buying and selling entirely and settle in a museum.
Each category is consumed differently. Transient goods are consumed by being used up, and rubbish is consumed by being thrown away or processed, as at a sewage works. Durable goods cannot be consumed at all, which is why true rubbish should not be sellable.
Whether something counts as lasting or disposable is a social judgement, not a fact about the object. People near the top can make things durable or transient, so they can keep their own possessions durable and others' transient. A neighbourhood called a slum, which is simply rubbish housing, may be a label the powerful apply wherever it suits them.
Rubbish is what we throw out of our lives and also out of our minds. What counts as garbage feels obvious and natural, so ordinary economics leaves it out. Yet the passage through rubbish is exactly where value gets created and destroyed.