air and heat vent removal

[wkbayer]

i have a 1990 1 ton 4x4 gmc i want to remove only the vents to clean them any suggestions

 

[98trck]

on a truck that old the plastic has hardened and you take the chance of it breaking easily
use compressed air thru a small diameter hose pushed in to the vent with the truck fan on high and other vents plugged/covered in some way