I've recently purchased a home which has an old wood furnace. I've never dealt with a wood furnace before but it seems pretty staiight forward and works well. The only issue I have is with the door on the furnace. There is no seal around the door just metal on metal when shut. There seems to be a large build up of tar looking creosote around the door, when the fire starts to cool down over the night and I go to open it in the morning the door sticks shut badly from this build up. Can anyone suggest a fix to this? From me yanking on the door as hard as I am I am scared the door will bust free from its latches. Which it is already getting a little sloppy in. Any suggested help or guidance here would be greatly appreciated.