Rattles! Driving me nutz. Dynamat Q’s

Guys, I think I finally shook the rear shelf loose enought to where it rattles like there's no tomorrow, it's really pissing me off, and of course, making my system sound like poo. I know it is the shelf doing it, I did a full inspection of everything that is bolted and related to the shelf and nothing is loose.. I have a 93 Mazda MX6 with a large rear hard plastic shelf. My question is where to actually put the Dynamat to get the best performance and get rid of the rattles. Do I stick it underneath (in the trunk) or do I remove the shelf, stick it to the metal underneath that, then re-install the shelf? Any other thoughts? Please feel free to share em, I've never used Dynamat before since I have usually always had a Hatchback or Jeep. Thanks! Todd

I would do it between the shelf and the metal, and if you have enough, go ahead and do the underside of the shelf inside the trunk too! You can never have too much in my opinion. Jeff