My TB's exhaust valve cover was cracked and did similar things, but in a different area than what you are seeing. Mine are plastic; not sure about yours. If your intake valve cover is loose or cracked, maybe that's your issue.

Larry

 

I would clean it up then run it for a short time, then check to see where the oil is coming from. If you run it for a short time you should be able to read the oil spill pattern to see where the source is. my .02