i was tired of having rear deck rattles, so i went to my local hardware store and got some 3m spray adhesive and some carpet underpadding and went at it.

before this i had peel and seal which worked great for about 15 mins, then the sun melted it

its been 3 days with the carpet underpadding and the 3m spray seems to be holding the padding upsidedown in the trunk and stopped most if not all rattles

i dont know if this method has been mentioned, if it has...disregard this post...just a cheaper method to reduce rattles other than dynamat, rammat, fatmat and all those other things