When I went to clean the chimney this fall I discovered a tissue paper thin shiny glaze of creosote lining the entire chimney. There was no loose stuff to knock off. Toward the end of the season the passive catalytic converter on my jotul 500 failed, causing abnormally Smoky fires before I caught the problem. My question is this a dangerous amount of creosote? The chimney sweep that came out to look at it said it needed to be chemically stripped and wants to charge me $4,000. Since it's so thin I wonder if it really is a hazard. Unfortunately I don't have experience with the situation. Thanks, John