how do you remove the defrost dash vents on a 1968 truck?

[texjake]

How do you remove the defrost dash vents on a 1968 truck? I was tearing into my dash the other day & removing the AM radio, the dash speaker, the ash tray & all the defrost/AC vent hoses & could not figure out how to remove the defrost vents in the dash & did not want to try to force them too hard & break them because the plastic is kind of brittle. I did a search here on the forum threads and did not find anything that could help me remove them without damaging them.