I have a fireplace that I can't get to stop smoking into the room. I am burning dry seasoned wood. It is a 2 sided corner fireplace with glass doors. I've read you shouldn't burn with the doors closed but when I open them I get smoke in the house. If I open the doors a few inches the smoke will stay in the fireplace but when open them further smoke rolls out the top of the door frame. The back of the firebox is straight and I dont believe there is a smoke shelf. The old damper is missing and the opening is in the back of the firebox. I have a top sealing damper on it now. The smoke that comes out is a fine light smoke you cant see unless you shine a flash light on it. I attached some pictures of the firebox. It appears that there could be some kind of shelf over the front of the firebox I cant see very well through the damper frame. Would it be a good idea to cut out the old damper frame to make the opening bigger?