Here’s a quick tip: Use the ambient occlusion node in a “magic” way to generate procedural leaks / streaks, for large built objects.
You can experiment with different textures for different looks. Works well, but is a bit slow due to the AO node. Does not work in Eevee.
(I also posted this on twitter)
Brilliant.
Awesome tech !!!
I give this a try right away ! 
And no idea why this topic got so few posts 
happy blending !
I added your nodes setup to my dirt textures bake
It is really amazing !
I did do some tryouts but didn’t manage to handle sharp-edges on a soft shaded object :-/
However the result is really amazing !
In blender:
And in unity3D:
I wish that one day, leaks on surface in blender are as realistic and straightforward as fluids 
Thanks a lot for this great piece of realism enhancement 
