I bought a vintage Pacific a couple of months back. In the tender was a 3 inch speaker surrounded by a half inch of hot glue. I poked at the glue with an X-Acto knife and could not dent it. Then I remembered this rubbing alcohol trick.
Using two Q-Tips I slathered the glue with the alcohol. After letting it sit for a few minutes, I pried up the corner of a blob with a popsicle stick. After a bit more prying I got a fingernail under it and lifted it more. Once I got the tip of my finger under it, I was able to start peeling it off. Took a bit of time and strength, but it all came off clean in one piece. The black wire is just some redundant track power wire from the front truck.

Now I can start restoring the tender so I can add a battery and receiver.