More Islanders are shunning paper coffee cups for reusable mugs, but one major fast food chain insists customers use the store’s disposable ones.

While most independent coffee houses and coffee giant Tim Hortons allow reusable mugs and even offer discounts, McDonald’s doesn’t permit it.

McDonald's said it is trying to protect their customers from contamination.

"We can't control the cleanliness of the cup that's been through the drive-thru or the restaurant, so this is the main reason why, for the moment, we prefer serving coffee in our cups," said Jason Patuano, spokesman for McDonalds.

But other operators said hygiene is not an issue.

Trevor Pharaoh, a server at Beanz Espresso Bar and Café in Charlottetown, said customers enjoy the environmental aspect as well as the discounted price for bringing your own mug.

"We wash our hands before and after, and use a disposable spoon or a fresh spoon, so there's no cross-contamination," he said.

"We'll go one size underneath. If you bring in a larger cup, we'll charge you for a medium. It's good business, it's good for the customer, good for the environment."

It requires less material to create the disposable cups, and cuts back on the waste left in trash cans and on the streets.

Tim Hortons offers a $0.10 discount for a reusable mug, although often the server first fills a paper cup before transferring it into the mug. The paper cup is then tossed.

Tim Hortons said it's not policy to do it that way and are informing staff of the proper method — filling the mug directly.

"That could be an education or a training issue for sure because, certainly, our corporate policy is that's to be filled directly and not to waste that extra cup. So that's something we'll have to look into," said spokesman Greg Smith.

Tim Hortons is also recycling more paper cups.