There are a couple of options to consider when cleaning up old charcoal and ash after a cookout. Just remember that you should never dispose of or handle old coals until they are completely cold.
Suffocate the fire – Simply close the lid on your grill, and shut the vents until ash has completely cooled, at least 48 hours.
Spray away – To speed things up, you can spray coals down with water before suffocating the fire.
Drown ’em good — By pouring water over the charcoal and stirring, you can cool ash quickly and completely, eliminating the possibility of dormant embers re-igniting.
Disposing of old charcoal and ash.
Once your used charcoal and ash is completely cold, you can throw it away. We recommend wrapping completely in aluminum foil before tossing into a non-combustible outdoor trash receptacle.
Give gently-used coals a second life.
If you’d like to re-use partially burned coals to fuel your next grilling session, do not extinguish them by submerging in water. Instead, carefully spray down your coals with water to prevent further burning. Once completely cooled, partially used coals should be allowed to dry, and kept in the grill for later use.
Cooling your coals.
To eliminate the possibility of accidental flare ups, always cool down old charcoal and ash. Here are a few common methods for extinguishing and cooling coals.
Don’t compost or fertilize with old briquets.
Both Kingsford® and Kingsford® Match Light® briquets contain ingredients other than charcoal to make them efficient cooking fuels. Charcoal briquets do not aid in the breakdown of organic matter.