Grilling with a gas grill is often cleaner than cooking with a charcoal grill. Some gas grills use aluminium tents over the burners to reduce flare-ups from dripping grease. Another way to reduce flare-ups and create even heat is to use lava rocks, which evenly distribute heat while trapping grease. Using lava rocks requires a little preparation before placing them on your gas grill.
Fill a bucket or large container with clean water. Place the lava rocks inside the container of water and mix with your hand.
Lift the lava rocks out of the water and place them on a flat surface in the sun. Allow the sun to dry the lava rocks completely. Turn the rocks over as necessary to dry. This removes the dust and flakes from the rocks that occur during the manufacturing process.
Open the gas grill and remove the cooking grate. If your grill has aluminium tents over the burners, remove the lower grate and lift the tents off the burners.
Place the lava rocks on the lower grate above the burners in a single layer. The sides of the rocks should be touching one other as much as possible, with no large air gaps between rocks.
Insert the cooking grate back into the grill. Turn on the grill and set the temperature to "High" for five minutes. This heats up the rocks so they evenly distribute heat to your food.
Turn the lava rocks over after five cooking sessions. Turn the grill on "High" for 10 minutes when you turn the rocks to burn off any excess grease on the lava rocks. Replace lava rocks when the existing ones begin to break apart or get extremely greasy.