What is an airwash system?
This is a system where secondary air is drawn into the stove (by combustion) through the top vent slide and deflected down the back face of the glass, thus reducing the smoke coming into contact with the glass and depositing soot on the glass. It does not mean that you will never have to clean the glass, but substantially elongates the periods between having to do so. The air wash system works best when burning dry wood. Wet and pitchy wood will produce more deposits on the glass. Also, deposits will form on the black of the glass when the stove is operated on low heat for extended periods. To clean the glass either use an oven cleaning fluid or dip a wet cloth in the wood ash (not coal ash as this may scratch the glass) and gently rub clean. Only do this when the stove is cold and ensure the glass is dry before re-lighting.