Backflow incense flows down through a backflow burner & creates a mist around the product This item must be placed on a heatproof surface When backflow incense burns the mist it creates can leave a light residue on the burner & the surface the burner is placed on This is from natural oils & resins within the incense & can be wiped clean with a damp cloth Never leave burning incense unattended Our small backflow burners come with a small foam mat that the burner can be placed on when in use however this is not heat proof so as stated above the burner must be placed on a heatproof surface before using (1 Random Supplied Of Shown Designs)