There are some nifty ways to play the commodity manipulation game, it seems. The Times article describes how Goldman Sachs Group Inc (NYSE:GS) uses its vast network of storehouses in the city of Detroit and its environs to make several layers of profit off of the same hunks of metal by moving them from one storage facility to another. This not only helps build in more storage time, but also increases the rental fees, generally based on the tonnage of metal on hand.