White coals mean high heat, not cold ashes. After cooking, place hot coals in a heavy metal container with a lid, or pour water on coals and stir them to extinguish. Recently in Boulder County, a fire started by hot charcoal in a grill next to wooden siding destroyed a home. Propane grills are dangerous when they leak. Check the valves and connections by spraying soapy water on them.
Bubbles indicate gas escaping and loose connections.
Clean the fire bricks to remove grease and food residue that will cause your fire to burn too hot. Use charcoal and propane grills outdoors in a well ventilated area to prevent carbon monoxide poisoning. Flammable liquids should be stored away from structures, where pilot lights can ignite fumes. Many home improvement projects use flammable stains, cleaning agents, gasoline or oil. Rags soaked in these materials are highly flammable and can spontaneously ignite a fire.