These bowls are used for mixing everything from cake batter to turkey stuffing. No kitchen should be without a goodly amount of these bowls. In a commercial kitchen, they are usually either stainless steel or aluminum. Like many other heavily used pieces in the commercial kitchen, mixing bowls are bound to wear out, but there are things you can do to lengthen the life of your mixing bowls. As with all things metal, to prevent scratches and deep gouges, never use metal utensils in your bowl. Try to stick to rubber or silicone instruments. Likewise, when cleaning, never use an abrasive material to scrub the bowls. Steel wool may seem like a good idea at the time, but it can severely scratch the metal of your bowl. For stainless steel mixing bowls, try to avoid placing or mixing acidic foods (fruits, salad dressings, vinegar) in the bowls for a long period of time. The acid can do damage to the steel, causing stains or pitting. Always wash your bowls as soon as possible to prevent stains from becoming permanent. While not always convenient, it is highly recommended that you wash your stainless steel and aluminum mixing bowls in the sink with a cloth and warm, soapy water rather than in the dishwasher as some of the minerals in the detergent can damage the bowls over time.