I believe I am misunderstood and/or incomplete. If you wish the inside different than the outside you will have to give it a different material. Did you ?
Everything has a bit of glossy, even ashes. In your mix node you still have 0.200. try 0.05.
Also, the color of the glossy shader is white, try some gray or connect the color of the top image texture node as I did. You might achieve the opposite effect. If so, you will need an inverter node.
