SASKATOON -- A City Park coffee shop wants to help customers think about the environment when buying take-out coffee.

City Perks has been offering a 50 cent discount for a few years on all coffee drinks if costumers use their own reusable mug. They took to social media to try and see if this is the best approach or if they should charge customers for disposable cups.

About 15 per cent of customers bring their own mugs.

"You can bring them in and we'll even clean them out for you. If they need a good scrub, we can even scrub them out for you," barista Kaitlyn Streilein told CTV News.

Matt Wolsfeld with the Office of Sustainability at the University of Saskatchewan said getting people to switch is doable, but won't be easy.

"One of the biggest enemies of sustainability is convenience and it's nobody's fault. We've grown up and live in a culture of incredible convenience. But we're going to have to give up some of our convenience if we want to reduce impact in terms of waste or energy usage."

Consumers are capable of change as witnessed with the switch to reusable shopping bags, he said.

"The concept of social diffusion takes place where you start seeing other people bringing in their bags and it starts to create a cultural norm. You realize that other people are doing it, it's OK if I do it. It might be proper to do it or I might be looked down on if I don't do it."

As of Jan. 1, Loraas stopped accepting reusable coffee cups with any wax or plastic lining, as well as black plastics.

Correction:

A previous version of this story included an incorrect description of discount for costumers using their own reusable mugs.