The entire point of these exchanges is to deal commodities for delivery and in the past investors and speculators who didn't want delivery got into some trouble when they forgot to sell out of their futures positions before the maturity date. Indeed even the great (if you like that kind of economics ;) ) Keynes did this accidentally once whilst trading his Cambridge college's funds and they ended up filling the college chapel with grain whilst they worked out what to do with it! This story may or may not be true but always bears repeating: from the Economist.
These days the majority of people trading commodities are investors and speculators and even the majority of end users only use the commodities markets to fix a price and then take delivery directly from a producer rather than through the market. There are still, however, traders on the markets trading contracts that are stipulated as being "for delivery". The majority of these are agriculturals or non-precious metals and you have to have a relationship with your broker, and probably the exchange, to trade these as there are extra costs and considerations attached to for delivery contracts; particularly the cost of delivery to the end point where you need them.
Incidentally, although precious metals contracts are normally not for delivery this is because even people who want to hold the physical commodity want their broker to store it for them for security reasons. I'm not sure that I would want a pile of gold under my bed...