The biggest threat to a quality blade is rust. That is true whether you have a fixed blade knife or a folder. Because of this, every knife owner should use the best oil possible on their knives.
Food-safe mineral oil is the best type of oil to use on all types of knives. It protects the blade and other parts of the knife from rust and will also keep pivots on folding knives moving. Mineral oil is also food safe, doesn’t go rancid, and is cheap.
I started using mineral oil on my Swiss Army Knives over a decade ago and now use it on other knives as well, including larger fixed blades. In this article, I’ll explain the different attributes that make mineral oil the best option for keeping knives protected and working properly.
Which Mineral Oil Do You Need?
There are different types of mineral oil, so make sure that what you are getting is food-grade. This will help keep you safe when using your knife for food prep and game processing.
The easiest and cheapest way to get food-grade mineral oil is to get it from your local pharmacy or supermarket medicine aisle. It is used as a laxative and will be clearly labeled as “mineral oil”. While it is a laxative, the small amounts that will transfer from a blade to your food would be minuscule and unlikely to cause epic bouts of the poops.
Related: How to Clean a Swiss Army Knife
Just in case you were wondering, the minimum daily dosage of mineral oil is 15 mL for adults. You won’t ingest anywhere near that much when using a knife that has been coated in mineral oil. If you are worried about it, just wipe the blade before use.
Rust Protection and Lubrication
Like other types of oil, mineral oil can be used to protect metal surfaces from rust. It works well whether you are trying to protect a large blade or small moving parts within a folding knife.
When using on larger surfaces, simply dab a little bit on a cloth and rub it on your blade. A light coating should be enough to protect against rust. For smaller surfaces, such as pivot joints, dip a Q-tip into the bottle and place it into the joint. Moving the blade or implement back and forth will help spread it out.
Food-safe mineral oil’s viscosity also makes it great for using on knives. It isn’t so runny that it will make a mess in your pocket or sheath. However, it isn’t so thick that it makes blades or moving parts sticky.
Mineral Oil is Food Safe
Another reason why mineral oil is the best oil for knives is that it is food-safe. This will allow you to protect and maintain your knife without having to worry about toxic chemicals. You also won’t have to worry about your apples and cheese tasting like WD-40 or Breakfree CLP, which is nice.
It Doesn’t Go Rancid
Many people like to use vegetable oil on their knives. It does a good job protecting metal and works well on blades that are used regularly. However, over time, vegetable oils can become rancid. Rancid vegetable oil can give a bad taste to any food that the blade comes into contact with. If you ingest enough of it, rancid vegetable oil can cause bad stomach discomfort. If you are out in the field, prepare to use a bunch of leaves in the near future.
In addition to going rancid, vegetable oils can also polymerize over time. This will make it sticky which is a huge problem, especially when dealing with knives that have moving parts.
Mineral oil, on the other hand, does not go rancid or polymerize and has no expiration date. That is one reason why it is used on food preparation surfaces such as cutting boards. I have been using the same mineral oil for around 11 years with no problems.
Mineral Oil Isn’t Messy to Use
Another great thing about using mineral oil is that isn’t messy to use. I am not a huge fan of using aerosolized oils and cleaners on my knives. It tends to get everywhere and is wasteful. I don’t like spraying oil on something with half or more of it ending up on the rag that I use to wipe off the excess.
When it comes to smaller items such as knives, a little dab will do just fine. Rags, cleaning patches, Q-tips, and your fingertips are all that you should need to apply oil to your knives. The bottles that food-grade mineral comes in are perfect for this. If you need a more precise applicator, pick up a needle oil applicator bottle such as this one. You will be able to refill it as needed.
It is Cheap
The last thing that makes mineral oil the best oil for knives is that it is very inexpensive. As of writing this article, mineral oil costs less than $2.00 for a 16-ounce bottle. If you combine that with how long it lasts and how little you need at a time, it is extremely economical.
Mineral oil’s low cost and high value are the main reasons why I haven’t tried more expensive oils on my knives. While there are other excellent products available, I have a hard time justifying their additional cost when mineral oil is so cheap and does everything that I need it to.