Justified question... :o) For steam cooking, water must be put into the dish, then the insert for cooking (stainless steel separation from the water) and the lid on top. The water is in the bottom part of the dish, which is made of coated material. Because it is coated, it is easy to clean. During the last cooking there was some residual material from the dripping of the food in the remaining water, so depending on what you are cooking, you can't avoid a quick rinse. As mentioned above, this is very easy and quick because it is coated.