How to remove plastic shroud in video card cooler?

I don't think when you remove the plastic cover it will cool better. It's designed to work with the plastic "air tube" like some sort of windtunnel to get the air flow over the whole part of the card, when you remove the tunnel it spreads the cooling air just in the air in stead of the card.
Don't know if you can remove it to clean. Maybe try an airpump for the wheel of a bicycle or something ?