Problems with removing thicker sound-deadening tar.

I’ve tried the dry ice method which works great for the thinner portions in the rear, but the thicker portions under the front seats and on don’t seem to freeze no matter how long or how much ice I use. Not even the slightest hint of a crack. It just gets cold without coming off any easier. I do this at night, but it hasn’t been very hot lately anyway. I’ve tried the heat gun method too, but by the time you use enough heat it turns into a goopy mess.

Anyone have any luck getting the thicker material off as cleanly and easily as they did on the Team Integra article or this Honda Tech one? Anyone’s floor completely clean or did you just put the carpet back over the residue?

BTW I wonder if this would work? Freez-IT