Smoke spillage is when smoke comes back into the room instead of going up the chimney. This can affect air quality and indicates the stove or flue or chimney is not working correctly. It may set off your carbon monoxide alarm.
Creosote is a sticky mix of tar, soot, and condensation that forms inside chimney liners when wood burns. It is highly flammable and one of the main causes of chimney fires.
You dont really think about how your chimney works until it doesn't. It's just a hole in the roof to let smoke out isn't it? Well there's a little more science in it than that.....