A picture would help. I can't understand much of anything from your description.

Is this an electric baseboard heater? I've never seen one glued to a wall. I suppose it's possible, but I sure wouldn't use adhesives on something that gets hot.

Since you've presumably removed the heating guts, it's not going to heat itself now, so you might try playing a heat gun over it to see if you can soften the adhesive, if any.

If that doesn't work, go the other way -- pack dry ice up against the stubborn part. Sometimes that will make adhesive brittle and shrink what's glued enough that it will break free.

Failing that, try a nice, big pry bar.

That's all I have. :(

Thank you for the suggestions! I'm about to try them now. Here are some photos for clarification:

Here's the one that I'm working on. The corner piece is loose, just stuck under the darn backplate. That is the old fin jammed back there as a makeshift pry bar.

The state I'm trying to get it to (after a little drywall repair). I'm keeping the heating element.

The finished one in the bathroom. Just trying to switch from nasty old covers to new ones before the kitchen floor goes in.

I have been using the old fin to pry, but will try a real pry bar.

I initially tried using a reciprocating saw to remove the nails from the last heater cover, but the commonly available blade lengths couldn't reach. I ended up making do with a mini pry bar and hammer. I imagine I would need the same length to remove whatever adhesive seems to be at the bottom. I've only found a long enough blade for $80, and would like to avoid spending that much except as a last resort.

I am leaving the heating element in place. Are a heat gun and dry ice safe options in that case?

I appreciate all the help. I'll check back for further answers and update this when I get the stupid cover off.

I can't see it very well in your photo, but a good pull upwards may separate the top from the mounting plate on the wall.

That's not electric.

Since it's nailed in, there may also be glue behind it. I've gotten up to 12" blades for my sawsall, and they weren't $80. There are blades out there for cutting into walls that will do fine on nails.

saw blades

I have the same problem!! Why would people.glue these in! How did you get them off?

A friend with a reciprocating saw came to help, and it turned out the covers in this corner also had nails placed directly behind the pipe! He was able to just saw through them.

P.S. Here's the same corner now. Part of me still can't believe I ever got that project done.

Those are nice covers. Where'd you get them?

Thank you! The one I just posted is from this website: https://ventandcover.com/

The bathroom one is from https://www.ezsnapcovers.com/. They have cuter options, but a bit higher price

You're not going to get much heat from that radiator with the piece of furniture up against it.

And you may want to check if the manufacturer has anything to say about clearances to potentially combustible surfaces....not only the furniture, but something that could inadvertently fall into that crevice.

This was all done before winter, and I did look into the safety first. These are hot water baseboard heaters which are a bit safer than the electric ones, but I appreciate you looking out for me!

I wasn't thinking of safety, more heat performance.

If you can move that furniture piece even 6 inches away from the radiator, it will work better. More would be better.

@HU-61956930 If that orange kitty is anything like mine, he will have moved the shoes out of his way and taken over that nice cozy heater nook by now. :)