Generally the only time you may need to clean your glass is after a long overnight burn. If you find that you have a wet sticky black film on your glass (creosote), it is better to burn the woodheater as normal for one load of wood, with the air slide fully open. When the wood has burnt down to a hot bed of embers, open the door and leave it wide open until the glass cools sufficiently to be wiped with a damp cloth. This should clean all the white smoky film off the glass. Creosote on the glass is normally a sign that you have tried to get too long an overnight burn or you have burnt excessively wet or green wood. If the film on the glass won’t come off with a wet cloth, you can use wet ash from the ash bed as a cleaner or commercial products such as Crystal Clear, Johnson Foam Clean or Windex.