Cooking live rock (not curing rock) is a process that rejuvenates used live rock safely and inexpensively, although it isn't actually cooked. I'm a huge proponent of using live rock in a reef tank rather than dry rock because of the beneficial biodiversity on and in the rock. If you want to re-use rock from an older system, cooking it will prepare it for the new setup. All you need is saltwater, a pump, and a suitable holding container. You may want to add a protein skimmer and a heater if the circumstances dictate it. And you need to let it 'simmer' for about six weeks or so to get the desired results.