Disassemble the top of your grill. Dispose of old rocks and charcoal sitting in the grill.
Soak the removable parts in a bucket of soapy water. Allow the parts to sit in the water for about an hour or until old food particles have softened. Scrub clean with a grill brush and rinse off the soap.
Scrape the inside of the grill and the rack to remove the food and grease. Do not scrape so hard as to scratch the metal. Sweep out the inside of the grill to remove the scrapings.
Wipe the outside of the grill with a cleaning cloth. Use a special cleaner if desired and buff out any scrapes or scratches.
Replace any damaged parts. These can be much cheaper than replacing the entire grill.
Reassemble the grill. Add new lava rocks and charcoal. Keep it covered from the elements until ready to use again.