I've always been interested how the trade in copper and other base metals works. I know precious has quite good liquidity via COMEX/CBOT, but from my research copper looks quite thin both on daily volume and OI. Is it possible to day-trade HG or is this more a position-traders market? Where do the commercial and physical players hedge(?): at COMEX or LME, maybe swaps? And the aluminum trade looks non-existent at the COMEX, so what's the story there?