I found an excellent argument in a recent paper by Svend Hansen,* clinching something in a particularly satisfying way.
Certain Bronze Age hoards in Northern Europe contain a lot of fragmented objects. But the pieces rarely add up to complete artefacts. In 2001 Stuart Needham argued that this may be due to a custom similar to that known e.g. from ancient Greece, where an animal was sacrificed and only certain parts that make poor eating were burnt as offerings to a god (a sleight of hand taught to humanity by Prometheus the trickster). Perhaps most scrap metal hoards from Northern Europe contain the gods’ share of a much larger collection of objects that were re-cast for renewed use.
The ideas behind Greek animal sacrifice are well documented in coeval written sources. Not so with North European metalwork deposition. But now Svend Hansen points out that though the Greeks never wrote about it, they were apparently also depositing scrap metal – and in exactly the manner suggested by Needham! At Olympia and other Greek sanctuaries of the 9th and 8th centuries BC, tripod bronze cauldrons dedicated to the divinity were often re-cast with only a few selected pieces taken aside and deposited in sacrificial wells or middens. This goes on at the same sites as the animal sacrifice that we understand quite well.
* Hansen, Svend. 2012. Bronzezeitliche Horte: Zeitliche und räumliche Rekontextualisierungen. Hansen, S. et al. (eds). Hort und Raum. Aktuelle Forschungen zu bronzezeitlichen Deponierungen in Mitteleuropa. Berlin.