To do this I used the original bag and cardboard header from the whistles, a bit of magnet and some metal plumber's strap.
As a bonus, this rig added some weight to the bag, which helped the actors to toss it across the stage like they needed to.
Jesse Gaffney is a prop master in Chicago. This blog serves as a catalog of all of the, how-to, how-not-to, and hey-that's-cool lessons I want to keep record of. I try to post something new every five days. Please browse around, let me know what you think, and tell me all about your own propping adventures.