I'm in the process of acoustically treating my room. Empty glass bottles, beer bottles etc, filled with cotton are good at absorbing low and mid frequencies. However they must be pointed toward the sound source.
I need a way of adhering bottles to a wall by their bases so that they stem out horizontally toward the center of the room. I'd rather not damage the wall but I assume that might be out of the question also. What's most important is I know they won't fall down, as they will be over my bed as well.
The folk traditional way of creating a wall with them by mortaring them together would work to add a lot of mass that would work to block additional sound, especially the low frequency kind. However, you would need to be sure that you created a foundation for something with so much weight. Even a slab foundation would need to have a footer poured for that.
Do it right from the beginning if you only want to do the job once. It'll be cheaper in the long term.