What kind of ash, briquettes, lump, or wood? Ash is a component of fertilizers. If lump or wood you can use it in compost. I wouldn't use briquette ash because of the additives.
Can you use this product as compost or fertilizer?
No. 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.