Remove rubber carpet backing from metal

Does anyone have any ideas on how to remove the rubber backing and glue from the metal panels on the side of the boat?
I tried a heat gun and a scraper but it did not seem to work at all. I was afraid to use too much heat as there is foam flotation behind the panels. I am not adverse to harsh chemicals if they accomplish the task.

can you tell if it is Rubber Contact Cement ?
Try acetone or lacquer thinner on a 4" spot and see how that works.
It may have to soak for awhile and it evaporates quickly.
So you can't walk off and leave it.

Try paint stripper.

Cup brush on a 4" angle grinder or on a air grinder.

I used an air hammer with a chisel tip. Got to be real careful, hold it flat and go easy. Works great.

I just went through this on my boat and in my searching, I found the best was using brush cleaner. I used a 1 inch chip brush. I also used a plastic mixing bucket I think it was a 1 quart sized one I got from Home Depot or Lowe's. Brush that on and that glue will start coming off pretty easy. I started with a wire cup brush but that was taking far too long. One warning, the fumes will get to you if you try to use it inside. Use it outside or have VERY good ventilation and wear rubber or latex gloves. You should also get a lot of rags.