Turn off the gas burner and wait several hours until the lava rocks have cooled completely.
Put on a face mask to avoid breathing in any soot or debris that has resulted from the burning process.
Collect the old lava rocks with a metal scoop and deposit them into a plastic trash bag. Continue the process until all the lava rocks and debris have been removed from the fire pit.
Pour new lava rocks into the fire pit and distribute them evenly on and around the burner.