Making ice cubes without a tray is a simple and convenient way to get the ice you need for your drinks or other purposes. There are several methods you can use, each with its own advantages and disadvantages.
One common method is to use a plastic bag. Fill a plastic bag about halfway with water and seal it tightly. Place the bag in the freezer and freeze for several hours, or until the water is solid. Once frozen, break the ice into cubes by hitting the bag with a hammer or other object.