How to Use Charcoal Tablets with Your Incense: Place the tablet on a heat & fire proof burner or burn in a medium such as sand. Ignite tablet with a lighter, holding it to flame for a few minutes until it turns to gray ash. The tablet will develop a long-lasting, intense and regular heat. It will glow and remain hot consistently for around a half-hour and have no impact on the smell of your incense. Place loose incense, resins, herbs and powders on ignited coal tablet. Enjoy your favorite incense fragrance as it curls up in sacred smoke.