So what do I do with the leftover Hush-Mat?

I've done the complete floorpan on the Demon from the washer foot squirter all the way back to the rear seatbelt bolts with GorillaMat sound deadener. I have a piece left over, 18"w x 10' long. What should I do with it...and no, I'm not taking the doors apart to put it in there. Any ideas? Thanks