Leather trim panel skin hidden tear seam with disrupted fiber matrix

A vehicle interior trim system such as an instrument panel or a door panel includes a panel substrate defining a deployment aperture. An inflatable device such as an air bag is adapted to deploy through the aperture during a crash. A natural, tanned leather skin covers the substrate, wherein the skin has a tear seam corresponding to the aperture on a hidden surface of the skin. An aperture door may be fitted within the deployment aperture which is adapted to open against the skin in response to deployment of the inflatable device. The tear seam is comprised of a region on the hidden surface of the skin having a disrupted fiber matrix from exposure to an alkaline solution such as ammonia, bleach, sodium tetraborate, sodium hydroxide, sodium bicarbonate, trisodium phosphate, potassium hydroxide, and potassium carbonate.