If you're careless and tend to leave your knives lying around or in the sink, chances are you've struggled with rusty blades.
Water, as it turns out, is enemy number one when it comes to keeping your knives in mint condition. To be more specific, leaving water on them for a prolonged amount of time is a terrible idea. This is because most blades are made with a certain percentage of steel, which is very prone to rusting when left in water for a long time. The combination of both oxygen and water on steel causes a chemical reaction called corrosion; this reaction is what we have to blame for those unsightly red spots on our steel knives.
However, the good news is that these spots are often surface-only and don't compromise the overall quality of the knife itself. In fact, since the rust is only on the surface, a simple soak will remove the rust from the steel: a lemon juice soak, that is.
Begin by stirring together an equal ratio of lemon juice to warm water in a cup—make sure it's one that is tall enough to accommodate your knives. Then, stick your knife blades into the liquid and let them sit for 10 minutes.
Once the soak is complete, remove them from the liquid and wipe them dry with a washcloth or towel. This soak and the gentle rubbing motion of the cloth should remove the rust spots in their entirety. Note that this will also work with other types of silverware, not just knives.
Of course, this isn't the only natural (and simple) rust removal method. Using coarse salt in conjunction with lemon juice allows you to scrub the surface of the knife more thoroughly without using more abrasive surfaces (such as steel wool) that may damage or scratch the knife.
If you want to add salt into your rust-cleaning routine, blend the liquid lemon juice with the salt to create an abrasive paste, then rub it against and on those most troublesome spots. Just make sure you don't leave the solution on too long, because it can cause even greater damage to the knife blades, harming the metal permanently.
As with the soaking method, use a dishtowel or washcloth to gently wipe the knife down afterward.
Okay, so lemon juice is great. One quick soak or a vigorous lemon-salt scrub and rust is no longer a problem. But what if your rust returns?
Well, unless your habits change, chances are rust will return at some point. However, you can use the same method to clean rust off your knives whenever the spots occur again. It does no damage to the knives over repeated use, so long as you don't leave them soaking for too long, since acid can actually speed up the rusting process.
Old habits die hard... and thankfully, lemon juice and water will hide any future mistakes you may make with keeping your knives spotless!