I'm renovating an old house, and a couple exterior doors needed replacing. They were weird dimensions, so I'm going to modify the framing to fit standard 80"x32 doors. When I was removing the old door frame, I started taking down down some wall material. It's cement and lathe, and I want to put new wiring in too, so I was planning on removing some wall coverings and putting up drywall later. Anyway, as I was taking down this plaster and lathe, I came across some insulation that appears to have been sprayed in. I have no idea what this **** is, but it looks like it's going to make a mess removing it. I want to get rid of this stuff, and put in modern fibreglass batt insulation then do my wiring and drywall. The house was built sometime in the 20's, but the seller had no idea about anything about the place. He could basically only tell me the same things I could see looking around which was pretty useless. Here are some pictures of the insulation: Can anyone identify what this stuff is? It's extremely lightweight and airy. There's a small chunk resting on a piece of wood, and that small chunk came from me sticking a piece of scrapwood in and pulling it out. It looks like very fine grained offwhite snow or dust. Anyone ever come across this before? What's the best way to remove it?