You want your paint image (I used Boston Bruins logo) and also a scratch texture. I found that one free on the web. It has white where there are strong scratches, black for clean surface. We also need the negative of it but I make that on the fly with the Math Subtract node.

You blend the two textures with the Blender and that's your diffuse color.

The inverse (negative) of the scratch texture goes into a Fresnel_Blend which means we get stronger reflections where there are no scratches, and the strength varies correctly with the angle of incidence. That is the factor we use for the Reflection_Value. A slightly softened Reflect node is used for the actual reflection.

We also wire the inverse of the reflection value into the Diffuse_Value (because conservation of energy says so).

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)