Those who stop at Dunkin' for their iced java jolt will now have to bring along their own koozies as the company bans the infamous 'double-cup'. The practice, made famous in New England, involves slipping a foam cup over the plastic one used with iced drinks for extra insulation. An ad campaign targeted at the chain's customers in Massachusetts and Rhode Island notes that the method isn't environmentally friendly. Starting December 1, Dunkin' locations in the region will swap out their polystyrene cups for paper ones. Did you know this was a thing? Which other ways have you tried to become more environmentally friendly?