On that first image with the Color_Math node, why do you have a black chip in value2 on a multiply function?  That should be white for the function to work correctly.  White, imagine it being 1, multiplied by black, the equivalent to 0, will result as a final result of 0, no effect.  And in your second image, the math function is division, contrary to what Nerd suggested.  Did you try his suggestion and found that it didn't work?  There is no elaboration in your responding posts.  If everything hasn't worked to your satisfaction up to now, have you tried darkening the Specular chip on the PhysicalSurface?  I also noted that your emission chip is not completely black although there isn't any emission strength applied to it.  I would adjust it just to make certain that that channel isn't leaking light.