It looks and feels like cardboard paper, that is deteriorated. Never seen it before, Studs were covered with Rosin paper to hold it in.
If it is shredded leather, :mrgreen: which I have only heard of, that must be a very old house.
TY fellas this helped
Remebered the name for it and found it many times on the web:
Kimsul Insulation- Seeking new ways to introduce its products for consumer use, Kimberley-Clark created Kimsul, a home insulating product made of creped wadding, impregnated with asphalt. Originally, Kimsul began as insulation paneling for refrigerators. Later, the product appeared in automobiles as dashboard insulation.
Kimsul was promoted as the insulation with many-layer construction; unlike then-typical loose bulk insulation, Kimsul had layers stitched together to form a blanket of uniform thickness.
In connection with a famous 1948 movie, “Mr. Blandings Builds His Dream House,” starring Cary Grant and Myrna Loy, Kimsul was advertised as the insulation used in the dream house. The product was easy to install and was resistant to fire, moisture, fungus, vermin and termites. National advertising for the product urged consumers to “Wrap your home in a blanket of Kimsul.”
Earlier, Kimsul had been the standard material for insulating Navy quonset huts (prefabricated metal buildings) during World War II. It gave protection against the tropical heat and Alaskan cold.