Take a 3 x 3 box to a guy that does spray in insulation. Usually just call him and find out where they are working that day and stop by. They may not even charge you for filling the box if you leave it with them. They usually shoot out the guns at the end of the day and need to dispose of the insulation.

I get mine from a local refrigeration plant. They have big garbage looking bags that they fill up. I wish the shipping on them was less I would send them out to whoever wanted one. If you are in the MPLS/StPaul MN or western WI area let me know and I' ll let you know where to pick one up!