how would I do this?

[aebstract]

I haven't tried and my part isn't modeled yet, but I know I'm going to need/want to try this out when it is done. I'm wanting to put the wax marks from skateboarding on the edge of a concrete part. Here is an example of what I'm talking about:
http://truesk8boardmag.com/wp-content/uploads/2011/07/Pott-3.jpg
The dark area is from wax and the skateboarding on the ledge. What would be the best way to try and achieve this?

[Chad Holton]

It would be a texture. Since this shot is straight on, you could use the concrete portion of this picture and modify it for your needs. (if it's okay with the original photographer)