Ever removed a heating duct?

Just the regular metal kind that run up the walls? Im stripping wallpaper and Ive got to get them down so I dont have a patch of (awful) wallpaper behind it! I thought that you would just have to take out the screws and it would come down but Ive taken out all the screws and it wont even budge! I know it shouldnt be that complicated, what am I missing?! I googled it but nothing useful came up. Arggh!

I'm thinking they must have used some kind of adhesive under there... maybe Liquid Nails or something similar. Maybe if you could get a long, thin blade of some kind, you could slide it underneath and break the bond?

Yeah sometimes over time they just get stuck, or people glue em on So take a thin knife or some other object and pry around the vent slowly. Some coaxing may be needed, and make sure there is nothing in the vent that may be holding it on.

Ugg, I was wondering (but hoping not) if there might be glue up there. Ill give it a go with a razor blade and see if I can get it. Thanks!