Apple has a trade-in program in place for various products (some of which, like an iPhone, you can actually trade in at an Apple Store), and it turns out that heavily marketing that effort has been good news for Apple.

Over the last year or so, Apple has started marketing and pushing its trade-in program basically everywhere it can. With trade-in prices ranging from $100 (for the iPhone 6s) and up to $600 (for the iPhone XS Max), it’s a quick and easy way to knock off the sticker price of a newer device.

That increased marketing push from Apple has resulted in a big turnaround for the service. Tim Cook, Apple’s CEO, spoke with GQ (via MacRumors) about the company’s efforts in sustainability, including the trade-in program. According to Cook, a third or more of visitors to an Apple Store have taken advantage of the trade-in program, and the number is even “trending up”.

This year we’ve really moved the dial on getting the consumer to think about trade-in,” he said. “We were up to a third or more of the people that come into our stores that are trading in, and this number is trending up

The conversation also covered third-party accessories. While Apple admits that it can’t control what other companies do with their products, whether they’re aiming for the same sustainability efforts as Apple or not, it can at least try to nudge them in the right direction. The way that it can do that? The products it makes available in its stores, and especially the ones that boast the Made for iPhone (MFi) program.

But, while Tim Cook acknowledges that it can use some leverage in those cases, anything beyond that isn’t something he’s ready to “pre-announce”.

Going back to the potential for a green-themed distinction or mark from Apple…when asked whether he had a plan to encourage more of these third-party manufacturers to be more sustainable, Cook confirmed that something in the realm of a mark or badge for specific products that measured up to Apple’s high bar for sustainability isn’t off the table. “In a case where there’s something that is required from us, like for use of our mark and the case of the [Lightning] connector, yes, that is something we’re talking about,” he said. “I don’t want to pre-announce it.”

In related news, Apple just earned a reward and title of “Outstanding Brand” from the Corporate Information Transparency Index (CITI) in China for its environmental work in the region.

The full GQ piece is definitely worth a read. Have you traded in a device to get a new one from Apple before?