The dishwasher can cause certain materials to turn rusty, become warped, or form cracks, and can weaken the capabilities and lifespan of some cooking utensils. While the heat and detergent from the machine can protect your valuable cooking tools, it can also cause the wear and tear of these tools over time. The dishwasher is also a hazard for knives, which can cause them to warp, crack, or split from a heat and water cycle. Hand-washing of nonstick pans with soap and a sponge is a better way to clean them. A cast-iron skillet can last for years if you hand-wash it, but only if it is properly protected by hand. An insulated mug can also be kept warm while wearing a dishwasher, but high heat and pressure can damage its ability to maintain its temperature.