Have a Space Maker Duster I need a little help.....

I've finally got my car back and am taking out the almost 40 year old carpet, what a mess. My question is what do you use to get the almost 40 year old glue off of the metal on the backseat (fold-down) and the metal floor panel under the package tray. I think if I used a sander/grinder it would just load up the wheel.. Second question, I need to put some kind of sound dampener material in, open for suggestions on that too. But if I use it on the metal floor panel under the package tray what kind of adhesive could you use on a typical foil backed material to hold the carpet in place.....I'm open to any suggestions...
If it helps I got my Floorboard carpet and 2 yards of the same color for the fold down seat, panel, and drop back access to the trunk from Legendary. I've heard nothing but great reviews about them..