I loved the Tutorial about the glass.
Following the procedure for mental ray mia material i tried to do something similar looking and got

I have on the top edge a grey color reflection and dont know how to get it away. I tried a lot of things and went yesterday desperate

I have tried following things to come behind the secret or to cross it out:
1. I imported one glass from the tutorial files, the glass shows the same reflection ( I thought maybe a model problem)
2. I changed the HDR, same result
3. I deleted the spot light and put a new one with different angle
4. I put the render quality for final gather to 500 and for Global Illumination even up to 1000
5. I smoothed the glasses and even tried with dielectrical instead of mia got also this odd "reflection"?
Any guess, how I could get rid off it. I will start the model again from scratch and hope will get it better.