Laryngeal mirror is warmed before use by placing:
(a) Glass surface on flame(Ref. Dhingra, 6th ed., 384)Laryngeal mirror is warmed before use by placing the glass surface on flame to prevent fogging caused due to breathing.Putting back of mirror on flame or will heat its back surface also which when held against the soft palate of the patient, while doing I/L, will cause burn injury.
Glass surface on flame
Back of mirror on flame
Whole mirror into flame
Mirror in boiling water
Anatomy of Larynx