Old keys and other similar objects are predisposed to develop rust with the time. Fortunately, rust can be removed from older keys if you work with the right cleaning approach. Of course, you have to arm yourself with a lot of patience and take some risk. The vintage keys may break with abrasion. This is the reason why you have to be extremely careful in choosing your cleaning tools.
Consider the following tips on how to clean up your rusty keys without causing more damages:
Your first step should be to determine the age, desirability and scarcity of your keys before taking any actions.
Separate and inspect the keys. Place the brass keys on one side, and the patina ones on other.
Fill a plastic container with distilled white vinegar. You can use every other type of containers you have at your home, besides the metal ones.
Let the key to soak for several hours. Then take them out and rinse well. If the rust start to fade away, just rub the key with a wire brush to clean up the remnants. Submerge the key back in the vinegar solution if the rust staining persists. Allow it to sit like that for a few days.
After that take your key out of the vinegar. To finish just rinse studiously. If the rust persists, better take your key to a professional locksmith. He will know how to act in order to save your valuable key. Alternatively,he will make you anew one.