How to Fill a Hole

So, I have a space that I am trying to insulate. But it has holes. And the holes are made from wood and brick and tin and plywood and only god knows what else.
But fill them I must. So I am thinking. And also, through the holes there is wonderful tin and nice materials. But everything is covered with lead and asbestos and I just don't know what to do.

I guess I'll go stare at my holes some more.