Knife Maintenance: Simple Tips for Better Performance

Knives are tools. To perform to their full potential, they must be maintained properly. This is particularly true of folding knives, which are, by nature, mechanical devices. Like any other machine, if you want them to function correctly, you need to maintain them well. Fortunately, with a little knowledge and some simple tools, knife maintenance is relatively easy.

One of the most important things you can do to keep any knife functioning well is to keep it clean. Most knives are meant to be used, and that use can often expose them to dirt, adhesives, animal blood, and a variety of other substances. Left in contact with the blade for prolonged periods, these substances can promote corrosion or dry on the blade, making them more difficult to remove. As such, whenever possible, wipe your knife clean as soon as possible after use.

For fixed-blades, avoid sheathing a knife with a soiled blade, as dirt, blood, and other materials can be transferred to the inside of the sheath. Trapped there, they can scratch the blade and increase the possibility of corrosion.

To clean a sheath knife safely, use warm running water, a soft-bristled brush, and dishwashing soap to scrub dirt off the blade and handle. Then, dry it thoroughly with a cloth or paper towel.

With folding knives, try to avoid adhesives and other materials that can stick to your blade and potentially work their way into the knife’s pivot area. If your blade does get dirty or sticky, wipe it off as best you can before closing the knife to avoid introducing dirt or other substances into the handle’s interior or lock. At the earliest opportunity, clean the blade by wiping it with a cloth or paper towel moistened with rubbing alcohol, WD-40®, an adhesive remover like Goo Gone®, or a similar cleaner. Purpose-designed blade-cleaning products, like Flitz® polish, also work very well and can even remove minor rust spots. Always work from the spine side of the blade and avoid letting your fingers come near the edge. If wiping with a cloth isn’t enough, place the blade on a folded towel and scrub it with an old toothbrush and the cleaning solvent. Then, rinse it thoroughly with water and wipe it dry.

If you carry your folding knife regularly—as you should—it’s inevitable that pocket trash and lint will accumulate in the knife’s handle slot and lock mechanism. This is particularly common for knives carried loosely in a pocket, but is still a concern for folders carried clipped to the top of the pocket.

If your knife is very dirty, you might need to run it under warm tap water while scrubbing with a soft-bristled toothbrush and some dish detergent. For the inside slot of the handle, get a straw cleaning brush, typically used to scrub out reusable drinking straws. Once your knife is clean, dry it thoroughly with a towel and blow the interior surfaces dry with compressed air.

Another way of more thoroughly cleaning a folding knife is to use a Water-Pik® or similar dental cleaning tool. These electric flossing tools use a pulsating, high-pressure stream of water to clean between and around teeth. That same focused stream of water can also be targeted at the nooks and crannies of a folding knife to achieve a deep cleaning. To keep the water from splashing everywhere, get a large, clear, zip-top bag and poke a small hole in it just large enough for the cleaner’s nozzle. Open the knife and tape the edge and point with masking tape for safety.. Place it in the bag, seal the top, and insert the cleaner through the hole. Hold the knife through the bag with one hand and direct the pressurized water stream with the other. Empty the bag of water as necessary and repeat the process until the knife is clean. Finally, remove it from the bag, rinse it, and remove the tape. Blow the water out of the interior of the handle with compressed air and wipe it dry with a towel.

For the ultimate cleaning experience, you might consider investing in an ultrasonic cleaner. Available in a variety of sizes and price ranges, these cleaners use water and ultrasonic vibration to clean jewelry, gun parts, and other components with complex shapes and recessed or hard-to-reach interior surfaces. They are particularly helpful for older Spyderco designs with riveted handle construction and intricate lock designs like caged Ball Bearing Lock™ mechanisms, as they reach areas that no other cleaning technique can. Follow the manufacturer’s instructions for your specific cleaner and, once your knife is clean, remove it and dry it promptly. Make sure to blow any residual water out of the lock mechanism and handle interior with compressed air.

Peel-ply-textured G-10 and fiberglass-reinforced nylon (FRN) are very popular handle scale materials. Sometimes, however, dirt can accumulate in G-10’s fine, checkered texture or the Bi-Directional Texture™ pattern of FRN. The easiest solution for this is a quick scrub under hot water with a toothbrush and some dish soap or other mild detergent. Ultrasonic cleaners also make short work of cleaning the minute nooks and crannies of textured scales. As always, rinse your knife thoroughly after cleaning and dry it completely, both inside and out.

If, after cleaning your G-10 scales, they appear duller, you can restore their appearance by applying a few drops of mineral oil and scrubbing it gently with a soft toothbrush.

Unpolished Micarta® handle scales have a matte finish and a somewhat porous quality. Many knife enthusiasts prefer this finish because it offers a more secure grip and absorbs skin oils to naturally patina—or discolor—over time, giving the knife visual character. If you prefer a cleaner look or need to remove a surface stain, a toothbrush, a mild detergent, and a little elbow grease should bring it back close to its original finish. Once again, rinse and dry your knife thoroughly—especially if its Micarta scales are paired with a tool steel blade.

The process of cleaning a folding knife can also wash away any lubricant that was present on its working parts. A freshly cleaned knife should therefore be properly lubricated before it’s put back into service.

Oil naturally attracts dust and dirt, so don’t get carried away with too much lubrication. Use a high-quality gun oil or similar lubricant with an applicator needle that allows you to precisely control the amount of lube dispensed and where it goes. Alternatively, you can place a drop of lube on a toothpick and use it to apply it exactly where you want it. Put one or two drops on each side of the blade tang when it’s in the closed position and let them flow into the pivot. Then open and close the blade a few times to coat the pivot and the contact surfaces on the side of the blade.

In back lock knives, the outside radius of the blade tang is in constant contact with the lock bar, so put a small drop on the back of the tang to ensure these parts glide smoothly. Sometimes, the lock bar itself can stick and affect the knife’s action. If this happens, a small drop of oil at the lock bar pivot, allowing it to seep between the lock bar and the liners, usually does the trick.

One common issue with liner locks and Reeve Integral Locks (aka “frame locks”) is that the ball bearing for the detent mechanism, which holds the blade in the closed position, “galls” or scrapes against the side of the blade tang. If your knife suffers from this problem—especially after it is freshly cleaned—open the blade partway and look into the handle near the blade to find the protruding ball bearing in the liner or lock bar. A drop of oil directly on the ball usually solves the problem and smooths out the action. A dab of lithium grease applied with a toothpick is even better, since the grease is more viscous and will last longer.

While we’re on the topic of lubricants, we should also address oiling your blade. Knives with tool steel blades are naturally more vulnerable to discoloration and corrosion than those with stainless steel blades. This is particularly true if you live in a humid climate, use your knife for tasks that expose it to moisture, or carry it in a position that exposes it to perspiration.

One traditional method of protecting a non-stainless blade from corrosion is to coat it with a thin film of oil. Take a few drops of gun oil or a similar general-use lubricant and wipe them over the entire surface of the blade with a cloth or paper towel. This seals the steel to protect it from oxidation. If you use your knife to peel apples or for other food preparation, use a food-grade mineral oil or traditional Japanese camellia oil instead of a petroleum or chemical-based lubricant.

Similar solutions to protecting your tool-steel blade include silicone wipes or dry-lube silicone spray, car wax, or purpose-designed blade waxes. Again, if you sometimes use your knife to cut food, read the labels carefully and be sure to choose food-safe products.

Finally, you can simply do what many old-school knife users did and let your tool-steel blade develop a natural patina. This is a thin layer of surface oxidation that ranges from gray to deep blue, purple, or black. Unlike rust, which is destructive, this form of oxidation actually protects the blade. If you're impatient, you can also “force” a patina by dipping your blade in vinegar, coffee, mustard, and other substances that greatly accelerate the process. Once you achieve the patina you want, wash, rinse, and dry your blade and put it to work.

You may have noticed that all the methods described in this article involve leaving your knife in one piece while you clean it. We strongly recommend that practice. First, it allows you to clean any folding knife using the same methods, including designs with riveted construction that cannot be disassembled by ordinary means.

More importantly, in most cases, there is really no reason to disassemble your knife to clean it well. If you do choose to go that route, understand that you are crossing into a different skill set and a different level of complexity. Once all the component parts of your knife are clean, you must also have the skill, knowledge, and tools to put them back together properly so your knife operates as it should. The more complicated the knife and its construction, the more skill and attention to detail you’ll need.

No matter which route you take, cleaning your knives regularly will keep them in top condition so they serve you well when you need them most. Knife cleaning can also be an extremely therapeutic activity and an important “rite of passage” for all serious knife enthusiasts.