Though Starbucks and McDonald’s are backing a pilot program in which diners will borrow reusable mugs, you won’t find the cups at locations of those global chains. Instead, four independent San Francisco coffee shops are the testing ground for the effort, which is ostensibly intended to reduce single-use packaging waste.

According to Bloomberg, the program is the result of a two-year “moon shot” effort called the NextGen Cup Challenge, which (per its website) is backed by a “global consortium” of companies like founding partners McDonald’s and Starbucks, as well as Coca-Cola, Wendy’s, Yum Brands (which owns Taco Bell, KFC, and Pizza Hut), and Nestle.

These bold-faced corporate names are perhaps odd bedfellows for small, independent San Francisco cafes and coffee shops like Ritual Coffee Roasters, Salt And Straw, Andytown Coffee Roasters, and Equator Coffees. But bedfellows they are, as it’s these four shops that, as of Wednesday, are a reusable-cup testing ground that will let patrons order their drinks in cups from a start-up called Muuse, which was tapped by NextGen to pilot the multiple-use vessel effort in San Francisco.

Speaking with Eater SF, Muuse COO Lizzie Horvitz explains that when a patron at a participating shop orders a drink in a 12 or 16 oz Muuse cup, they’ll download the company’s app, then scan the QR code of the cup they’re checking out. They won’t pay an additional fee — in fact, they’ll get a 25 cent discount on the drink — as long as they return the cup within five days. Customers will again scan the QR code on return. If they lose the cup, or fail to return it within that five day period, they’ll be charged $15 via the credit card information entered into the app.

While the businesses involved in the NextGen Cup Challenge’s consortium haven’t announced a reason for their participation in the effort, there are a couple of reasons they might want to get into the reusable cup game. Obviously, concerns that the earth is being buried in trash are at play, but it’s also worth considering the profit that could result from absent-minded folks who drop $15 on a cup that likely costs far less to manufacture. Finally, it’s a rare company that has had its brand tarnished by a public effort to reduce waste — even if that effort is more talk that action.

For now, the pilot is extremely limited: each coffee shop has agreed to a one-month contract with Muuse, and only four locations are participating: The Andytown at 181 Fremont Street, Equator’s 222 2nd Street shop, the Hayes Valley Ritual (432b Octavia Street) and the Hayes Valley location of Portland-based ice cream chain Salt and Straw (586 Hayes Street).

According to Horvitz, Muuse chose the locations “very strategically,” as the SoMa shops are in a high-traffic “corporate” zone and Hayes Valley “sees a ton of people.” She says that the company also chose companies that “align with our ethos,” and are focused on Muuse’s goals of waste reduction.

This is Muuse’s first foray into the US market: It launched in Indonesia in 2018, then moved into Singapore and other Asian countries, where it operated with a model similar to what they’re planning in the US. That’s why, Horvitz says, the double-walled, stainless steel cups and (reusable) plastic tops they will launch with are made in the southeastern Chinese city of Shenzhen. “We were based in Asia for so long,” Horvitz says, and that factory was “closest to us,” but “now that we’re scaling we’ll definitely look into US manufacturers,” she says.

Another thing that Horvitz says the company is looking into are accessibility issues. For now, the participating cafes are also offering paper cups, so members of the disability community who find that reusable cups can be too heavy to lift will still have options. But if the pilot expands the way Horvitz hopes, that’s something that will have to be figured out. “We’re happy to engage” with the disability community on the matter, Horvitz says.

Related Blue Bottle Coffee Plans to Eliminate Cups and Bags From Two Bay Area Cafes

Though the contract with the four SF shops is only set to run for a month, Horvitz is hopeful that it’ll continue after that, and grow beyond it. Since the program is backed by some of the biggest names in the food business (it’s worth noting that Nestle owns Blue Bottle, which itself announces a reusable cup pilot for two Bay Area cafes), Horvitz hopes that if successful, it will spread to the masses. “The goal of this pilot is to have (big companies) see it working in the smaller cafes,” Horvitz says, and then, once the concept is proven to work, “we’d love to make it happen with a large company.”