Lots of things have been tried. Fabric / elsatic wraps, look cool 'till you use them, and the elastic fails quickly. Knotted Surgical Tubing, but it eventally rots. Inner tubes, but they can be hard to grasp, and it's hard t find the right size. Knotted Bungee cord, the knots are klugie, and unravel.
Need a clean solution?
DSS Stage Bottle Bungee Wraps. Furnished with a 2 piece Molded Delrin Clamp the DSS Wrap uses 1/4 diameter bungee cord. Reuseable clamp allows for fine tuning or replacement of the bungee. Two Stainless Steel screws hold the clamp securely together.
Available complete with quailty bungee cord (sized for an AL80) or as bare clamps ready for your bungee.