If its a nice piece and you want it in your tank you need to put it in a container that covers the rock compleatly with salt water and put a power head in with it and possibly a heater if you cant keep it to about 78 degrees, also I would not run any lights over it, do this and about once a week do a 50 to 75 percent water change until the rock doesnt smell any more, this could take a few weeks or just a few days, depending on the extent of the smell, just dont put in the tank until the smell is gone or ammonia spike will happen ....cya