If the components and the case are dirty or dusty, turn off the printer and clean them using a soft, clean cloth that has been dampened with water. If you cannot remove the dirt, try adding a small amount of mild detergent to the damp cloth.
Be careful not to get water onto the printer mechanism or any electrical components. Otherwise, the printer could be damaged.
Never use alcohol or paint thinner to cleanthe components and the case. These chemicals can damage them.