I ran into 2 types of sound deadening with my late car. One style is the rubbery stuff on the torque tube tunnel and the floor boards. The other is on the rear wheel wells and it is like fuzzy carpet. The fuzzy stuff a rag soaked in Xylene works perfect - soak the rag, place on fuzzy stuff, let sit for 10-15 mins, rub with soaked rag and it should sluff right off.

The rubber stuff takes more time and effort.

1-heat gub from harbor freight
1-putty knife
1-can of xylene
1- bag of 25 rags from harbor freight

use heat gun to heat a side of the rubber for approx. 1 min, use putty knife toget between metal and rubber, it prys off rather easily, repeat above steps until all of the rubber has been removed and only the glue residue is left, now take xylene with rag and scrub a dub-dub lol

Works awesome but is still time consuming. Also you can get the Nitrile gloves from Harbor freight.