Heavy duty. Microwave safe. Strong. Convenient. Compostable. With Hefty Ecosave, the heavy-duty strength and convenience you expect from Hefty are met with sustainability. Made from plant-based materials that are compostable in commercial facilities, using Hefty Ecosave means sending less waste to landfills. Compostable (Commercially compostable only. Facilities may not exist in your area. Not suitable for home composting) bowls.