Don't use firelighters - they can cause a 'milkiness' to appear on the glass. Instead light your stove the old-fashioned way, just using newspaper and kindling.
Hi, Thanks for this tip - I hadn't heard about this possible problem and a bit of searching online found very few references to it.
The gist is to avoid anything with ammonia in it - remember that stove glass is actually a precision engineered ceramic.
So your best bet is to avoid cleaning the stove door with anything other than "ashes and newspaper" and possibly avoid firelighters as well. I personally doubt that paraffin firelights would have anything in them that would mess with the door - we have been using them for years and don't see any milkyness.
Mike