My dash vents are pretty loose and mainly just hang limp most of the time. I can adjust them to where I want but after a bump or three they go limp again (pardon the expression!) Does anyone have a fix? I was thinking about inserting some thin black "C" shims at both sides of each vent but I have no idea where to get anything that thin which is also strong enough to push into place without bending or otherwise being mangled. Any feedback is appreciated.