Quote - Sweat stains on a sweat shirt like that aren't shiny they are simply a darkening of the cloth. Why go to so much trouble with nodes when you can burn in the stains? Or use the color mode and paint them in?

Well, this T-Shirt comes in many color variations and it would be good to able to just switch the image maps in the diffuse channel in stead of adding the sweat to every single image map.
One sweat map and one color map if you know what I mean.

But I think I´m getting pretty decent results in Photoshop.  I paint on top of the texture on a layer set to Overlay. Render to follow shortly...

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