http://ftalphaville.ft.com/2013/02/04/1368692/deripaska-on-the-collateralisation-of-aluminium/

Rather than remaining a pure consumption metal, aluminium’s attractive forward curve structure has turned it into an ideal store-and-pick-up free carry trade.

Since the curve in the aluminium market has for a long time been more than compensated for the cost of storage, that yield has often proved more attractive than other competing safe haven investments on the market.


http://www.telegraph.co.uk/finance/commodities/9845609/Oleg-Deripaska-bucks-trend-and-predicts-upturn-in-the-aluminium-sector.html