At least in the case of gold, there&#x27;s a very large retail market with lots of connections to the investment market, and as far as I know, gold is easy &amp; safe to store &amp; refine, so if you sell some scrap gold to a gold dealer they don&#x27;t have <i>too</i> much trouble refining it into something standardized. The rarer something is, and the more dangerous, the more you&#x27;re going to pay in costs.