Fill the trays with water and then slide the trays into fridge. Besides water, you can fill the ice cube mold with juice, pulp, ice cream, soda and wine to DIY cubes to your favorite flavor. And you can simply put them into your dishwasher after use. The big ice chunks cool the drinks much better than small cubes. The molds are very flexible so cubes pop out easily. Total 24 cavities can be used for making homemade soaps, jellos, candles with lovely heart ice cube tray shape.