Recuring involves putting the LR in a container (spare tank, clean trashcan etc.) with a powerhead and heater and protein skimmer(somewhat optional). The rock is then allowed to sit in fresh saltwater with good circulation to allow the die-off to rot away. Keeping a eye on ammonia and doing large water changes when ammonia is present will preserve a lot of life. Once the ammonia is gone and the rock smells fresh you can add small amounts at a time to the tank.