Can you imagine a world where the milkman still brings glass bottles of fresh dairy products to your doorstep and takes the empties back to be cleaned and reused? At first I was skeptical. But the more I think about it, the more I think the model can work. It doesn't have to be bad news for plastics processors. But it won't solve the industry's problems. Stay with me on this. Terracycle Inc. brought up the idea last month at the World Economic Forum in Davos, Switzerland. Terracycle is known for setting up recycling schemes for hard-to-recycle products, like cigarette butts and juice boxes. Some of the company's projects strike me as gimmicks, designed to take pressure off brand owners that sell unrecyclable products. At Davos, Terracycle announced a new service called Loop, which promises to use and collect reusable containers for a wide range of products. It's being touted as a replacement for single-use plastics packaging. Unilever plc and Procter & Gamble Co. are already signed up to participate, so expect to see products like refillable stainless steel deodorant sticks in select markets this spring. When I first read about Loop, I wondered how Unilever will sell deodorant packaged in stainless steel for the same price as product packaged in plastic. Not to mention the cost of picking up, cleaning and refilling the sticks. And if the price isn't the same, how many consumers will pay a premium for deodorant in stainless steel? It sounded like a gimmick. I was ready to write a column about the balance between convenience and sustainability and argue that convenience, which favors single-use plastics, will win. But the more I researched, the more I thought that this might be a few years ahead of its time, but it might work. After all, many consumers already get meal kits and groceries delivered to their doors. Why not encourage them to return the packaging through the same delivery system? There's no reason those vehicles have to return to the warehouse empty. Loop says it will use premium, durable packaging made from metal, glass and engineering plastics. If those are the choices, I like plastics' chances. Plastics have the edge when it comes to cost and carbon footprint. And when premium plastics containers have reached the end of their useful life span, they're easily recycled. All that said, Loop isn't going to solve the plastics industry's solid waste crisis. It's not going to collect fast food containers, cigarette butts or tampon applicators, which are among the most common trash items collected in beach cleanups. It's also not going to stop microplastics that come from laundering clothing. But it's a potentially encouraging development in what I expect will be a long effort to make consumers a little less comfortable with the idea of throwing away valuable plastics after only one use.