Getting behind dashboard air vents and also removing front 'shields'

One of my air vents (inner passenger side) has snapped and the gubbins are causing a real rattle. Also, on the underside of the car I've got some water shields on the cross member, they're barely hanging on now due to rust, would it be safe to remove them? They're making a noise too!


Edit : Managed to tweezer the busted parts out of the air vents like some ghetto version of Operation.