Starbucks is testing a new recyclable and compostable cup in some locations in New York, San Fancisco, Seattle, London and Vancouver.

The new version of the cup is still made from paper, and should look and feel the same as a traditional Starbucks cup. But inside, the vessel is coated with a compostable liner, rather than the plastic one used in Starbucks' regular paper cups. That means the new cup can be composted in industrial composters, unlike the cups Starbucks uses today, CNN reports.

"Customers will not see any noticeable difference from the current cup," the company said in a statement discussing the test.

Starbucks has been trying for decades to reduce waste by developing a greener cup. It's a hard problem to solve: Plastic-lined paper cups are light, stackable and effectively keep liquid from seeping out. And technically, at least, they are recyclable.

A few years ago, Starbucks doubled down on its effort to find a more eco-friendly cup by committing to the NextGen Cup Challenge. Starbucks (SBUX), along with food-sector rival McDonald's (MCD), committed $10 million toward the contest, which was run by recycling-focused investor group Closed Loop Partners. The challenge crowdsourced solutions and named several winning technologies, including the bioliner Starbucks is now testing.