The material that your cookware is made out of determines the cooking properties; each cookware material has its own particularities, and its own care and cleaning requirements.
Copper cookware that is unlined is excellent for certain specialized applications. The best uses for unlined copper cookware are bowls for whipping egg whites, delicate French sauces, and pans for sugary foods that are not acidic, basic or sulfurous, like jellies and jams. For cleaning, never use metal scouring pads; wash with a very mild detergent. Copper cookware requires some maintenance; if it begins to darken, that means it must be polished to make it shiny. Use a polishing cream that is copper friendly. Flour and salt mixed with white vinegar and lemon juice is a classic polishing cream, but there is more of a possibility that you could scratch the pan than with a proper commercial copper polishing paste. A small amount of copper will be transferred into the food; this is what helps egg whites to rise so much, and may actually have beneficial health effects.
On the other hand, consider cast iron cookware. Cast iron is the quickest heating metal, so a large sized, cold meat will heat up well. Produces beautiful searing and blackening, and fond production. Unfortunately, this material is dark so one can't see the fond color in order to gauge how well it is cooked. In addition, searing, fond production, and blackening of food is essentially a process of burning, which produces toxic soot and other carcinogens. As well, one needs to season cast iron. Le Creuset makes enameled cast iron which solves this problem. However, their cookware is very heavy. For cleaning, while the cast iron is still hot from cooking, add a little oil and salt, then scrub with paper towel; use salt as an abrasive and work fat into the micro-fissures. Dump the salt then wipe clean & store. It's true that acidic foods interact with the cast iron: you might not pickle lemons in it, but acidic tomatoes will cook fine.
In summary, be careful to choose your cookware material wisely, in order to improve the quality and speed of your cooking and meal preparation, and take care of your cookware properly.
