How to make clear ice

"Isn't a cocktail as much an experience for the eyes as well as the tongue?" asks Mr. Homegrown of Root Simple. "Thankfully it's easy to make clear ice free of cloudy impurities. His technique is to fill a small cooler with water and putting it in the freezer. "The insulation in the cooler will cause the water to freeze from the top down. The minerals and impurities in the water that cause cloudy ice will settle to the bottom of the cooler. Later, you will harvest the pristine, clear ice off the top."