If you want to do the work, clean very well, if cool out warm it up a bit, carefully applied, rubbed in well.....search for PS Ensolite, incredible stuff, I have used it for 15+ years and when running my business sold hundreds of thousands of yards of it. The original version is a thermal/acoustical foam developed for the space program by NASA and is fire retardant. It is the key element in low weight cost effective sound deadening any kind of vehicle and many more uses.
This info is just that, info, there is nothing better I have ever found and like to make sure others know about it.