I'm finally conceding that I'm not going to do anything more with the bale of 'acoustic' cotton insulation I bought.
I have two 2'x4'x3" panels with light burlap fabric covering on the front and wood slats on the back and two 2'x4'x6" double-thickness ones also with light burlap on the front. I also have a few (three I think) unused 2'x4'x3" pieces of the insulation and some light burlap left.
If you're willing to come up to Lousville (south of Boulder, just off 36) and pick them up, I'll let go of them cheap. Maybe something like $10 each for the thin panels and $20 each for the thick ones. $75 takes all four panels and the unused insulation and burlap.