I think all of us will run across this problem from time to time. Rust Stains on our knives. I can remember being given a knife many years ago that was so rusted that I debated whether it was worth trying to salvage it or not.
How Do Knives Get Rusty?
Perhaps you have put your knife in the dishwasher and somehow it has come out with a rust stain on it that won’t budge. Dish washers are notorious for “Floating rust”, which is caused by rust in a dishwasher which “floats” around during the wash cycle and lands on object in the dishwasher creating brown spots and rust spots. That’s one of the major reasons I don’t put my knives in the dishwasher to clean, combined with the fact that they dull your knives.
Did you also know that fingerprints left on a knife can cause your blades to rust? The natural salts which are present in your skin can react with the metal of a knife to create rust, so always make sure you wipe your knives free from any fingerprints after use. This is a handy tip to know.
Here are some other tips and advice on cleaning rust from your knives and then keeping them rust free:
Safety First: Never Use a Rusty Knife
Don’t ever be tempted to use rusty knives to cut or prepare food. Doing so puts you at a serious health risk, and your throat and digestive system can be injured by ingesting rust flakes, depending on their thickness. Better safe than sorry, especially when rust on your knives is usually quite an easy problem to deal with.
How to Remove Basic Rust Stains on Knives
Step 1: Clean with Water
The first thing you will want to do is to clean your knife with water. Before you can even think about removing the rust you will want to make sure your knife blade is scrupulously clean and free from any dirt or oils.
You can do this simply by holding it under running warm water using regular tap water. Try not to allow any water to get into the gaps between the handle and the blade. This can cause new rust spots that are difficult to get to. Once you have rinsed your knife, dry it off very carefully with a soft, clean rag, taking care to get into that gap!
Step 2: Try with Vinegar
Vinegar is a great help in cleaning rust from your blades. Nothing fancy here, just plain white vinegar does the trick perfectly. White vinegar contains acetic acid, which can go a long way towards dissolving rust.
You can dampen a rag with white vinegar and apply it directly to the rust spots, or if the knife is badly rusted, you can soak the whole rag in vinegar and wrap it around the blade, leaving it for a few minutes. Depending on the size of the knife, you can also soak the blade in a bowl of vinegar. This is particularly helpful for tougher rust stains. Once the rust has dissolved, rinse the knife under running warm water to clean off any vinegar and then dray well with a clean, dry cloth.
How to Remove Difficult Rust Stains on Knives
Baking Soda & Lemon Juice
Particularly difficult rust can be removed with the use of salt or baking soda along with lemon juice. Lemon juice on its own will work, but it is much more effective when used in conjunction with some salt or baking soda. They are slightly abrasive, without being overly so, and will dissolve when you add the lemon juice, making them completely safe to use.
Simply sprinkle the salt or baking soda (and by salt, I mean fine iodised table salt not your expensive sea salt flakes!) over the rust spots, and then wipe the blade clean with a soft clean rag which has been soaked in lemon juice. Don’t leave it on the blade for more than a few minutes as the acid in the lemon juice can actually damage the metal. Rinse away with warm water after a minute or two’s soak (no longer) and then dry the blade thoroughly with a soft clean cloth.
Baking Soda Paste
I always have a huge container of baking soda in my kitchen. It’s good for so many things. I use it to help keep my drains smelling fresh as well as my refrigerator. Baking soda can be very affective in removing particularly stubborn rust stains, although you may need to repeat the process a few times to remove the rust completely.
Simply make a thick paste of it by mixing a quantity of baking soda with a bit of water. You won’t need a lot of water, just enough mixed into some baking soda to give you a thickish paste. Measure some soda into a bowl and add cold water by increments until you have the consistency you desire. You want it to be thick enough that it will stick to the blade of your knife and not run off.
Apply this paste to the blade of your knife, completely covering it and then leave it to soak for a few hours, no more than three. After that time, the paste will have started to dry a bit, but it’s very easy to remove by using a wire brush or fine steel wool to scrub most of it off. Normally, I would never advise washing a knife with a steel wool, but this is one example where it’s necessary. Any remaining paste can then be removed by holding the blade under running warm water.
If you can see that there is still some rust on the blade, repeat the process. When all the rust has been removed, dry the knife thoroughly with a dry clean cloth.
A unique way of removing rust is by using something you will find in the vegetable bin. Yes, it is the humble potato, believe it or not! Simply stick the rusted blade of your knife right into a potato large enough to cover it and leave it there to soak for a few hours.
After that time, remove your knife from the potato and rinse away any potato residue from the knife blade under warm running water, once again drying it completely afterwards with a dry clean cloth.
No need to throw away the potato, simply cut away and discard the part that has been exposed to the rusty knife as there may be particles of rust clinging to it. The rest of the potato should still be suitable for consumption, however.
White Vinegar & Dish Soap
Another method of cleaning rust from your knives involves the use of a mix of white vinegar and ordinary dishwashing soap. Mix the two together in equal amounts and then apply the mixture to the blade with a soft rag, rubbing gently. Leave for a few minutes, then rinse away with warm water and dry off the blade completely.
For particularly stubborn stains you can leave the knife to soak in the dish soap and vinegar solution for up to an hour. Remove and rinse under warm running water and then dry completely.
The Toothbrush Scrub
You can also use things like old toothbrushes (I always keep mine). These are particularly useful in removing grease, lint, and dirt from knives. Simply apply some dish soap to the knife and then scrub it all over with a toothbrush. You can also use toothpicks or cotton swabs to get into smaller detailed areas, making sure that you rinse your knives completely afterwards and dry well.
Magic eraser sponges work well also. With them you don’t need to use any chemicals, lemon juice, etc. Just wet the magic eraser sponge with a bit of water and scrub, once again rinsing afterwards and drying well.
When Nothing Else Works: Rust Removers
Finally, and the most obvious way of removing the rust, will be by purchasing a purpose-made rust remover for knives, ensuring that you will be able to clear off any rust spots as quickly as possible. If you have a knife that has been particularly neglected, this may be your best option, but do be aware that there are limits to anything, and there is no guarantee that you will be able to budge the smudge!
Having said all of this, I want to conclude with the fact that an ounce of prevention is worth a pound of cure. Practicing responsible and proper knife care generally as a rule will help to keep your knives in tip top condition and prevent them from becoming rusted in the first place.
Marie Rayner is a Canadian, who moved over to the UK and began a new life in the year 2000. At the age of 45 she decided she needed a career change and went back to College to take a Chef’s course, after which she worked as a Personel Chef for a number of years.