Freeze old coffee
Thousands and thousands of gallons of day-old coffee go down the drain every month. It’s understandable, seeing as how old coffee isn’t just flavorless, but it’s also disgusting. However, you can make use of old coffee by pouring it into an ice cube tray and freezing it.
The coffee cubes will help cool a steaming pot of coffee down without diluting the flavor. This even works with coffees mixed with milk or creamer. Old drip coffee works best, and there’s always leftovers after everyone has had their morning mug. If you have leftover coffee cubes, put them in a zip-lock bag so they don’t absorb the aromas from your fridge.