More things to do with leftover coffee: Make coffee ice cubes! Are you the type that doesn’t like a lot of ice in your summer coffee drinks because it waters it down? Well this is the perfect solution! Pull out your ice cube trays and fill them with your leftover coffee. They freeze up just like normal ice cubes, and won’t water down your iced coffee! Keep them in the freezer in a well-sealed container (plastic bags work as well, but you take the risk of getting that plastic-y taste on them) and they’ll keep for quite awhile.