I think you need to whack the tube a bit if I remember correctly from Bay13.
You could just clean the hole going to the EGR valve and not the entire EGR valve. The passage is most likely clogged causign the light to come on. You may be able to get away with it during inspection but if the valve is really dirty, it'll come back short time later. I don't know how old the car is but likely the oil is getting by the valve guide ending up in the throttle body. Could try a heavy weight oil or get it to a mechanic to find the real problem.