To clean a copper penny, squeeze out a small amount of tomato ketchup onto the face and back of the coin. While you’re grasping the coin firmly by its edges, use a clean toothbrush to lightly scrub the flat surfaces of the coin. The salt and vinegar in the ketchup will remove tarnish from the penny. Then rinse the coin clean under distilled water and pat dry with a clean cloth.  This practice works best on pennies produced before 1982. Pre-1982 pennies were made using real copper, whereas post-1982 pennies contain zinc, which will not be cleaned with ketchup. Be aware that ketchup is mildly acidic, and so may end up reducing the penny’s value. Begin by running the coin under distilled water. Then, hold the coin firmly by its edges. Using your fingers or a clean toothbrush, apply a small amount of baking soda to the face and back of your coin and lightly rub. The baking soda will remove black and tarnish from the surfaces of the coin. Rinse the coin under distilled water again, and pat dry with a clean cloth. This process will be most effective on older silver coins. It may be less effective on newer coins that contain less—or no—actual silver. White vinegar is a common cleaning agent which many people use to clean metals, including jewelry. To clean an old coin with vinegar, pour a cup of vinegar into a glass or bowl, and then gently set the coin at the bottom. Let the coin soak for a few minutes. Then grasp the coin by its edges, pull it out of the vinegar, and rinse it clean with distilled water.  If the coin is still tarnished or dirty, try brushing it gently with a soft toothbrush. Be careful not to scratch the surface of the coin, however. If the coin does not look cleaner after a few minutes, place it back in the vinegar for a few hours. Very dirty old coins can even be left soaking in vinegar overnight.
افرك العملات القديمة بالكاتشب. نظف العملات المعدنية القديمة بصودا الخبز. نظف العملات القديمة بالخل.