I still think soda cans are just a better solution

That actually sounds like a good idea to me, or you could make them similar in design to those water-bottles that have the cap meant to stay with the bottle, shown in:

this image (branding removed)

Whereas the existing design is similar to the old pull tabs that were on cans which caused ecological damage when people discarded them on the ground.

I wish they'd instead go after the big companies doing the majority of the damage, but I suppose this's where the cards lay. (For now)