There are a few different ways to clean a Swiss Army style pocket knife, Leatherman-type multi-tool, or simple single-blade knife. The most important thing about knife cleaning is to do it often. If you let too much grime, grease, and grit build up, then it will be harder to clean your knife. So, keep it as clean as you can while out in the field and do a more thorough job when you get home. Additionally, always keep the hinges of your knife lubricated either with light cooking oil or WD-40.

Method 1: De-greaser and Lubricant – General Knife Cleaning and Maintenance

You will need: Either WD-40 or Break Free, a towel and a toothbrush.

This might be the simplest way to clean a knife. Unfold all the blades of your Swiss Army, Leatherman, other pocket knife or multi-tool. Using either a corner of the towel or a toothbrush, apply Break Free to the knife. The lubricant helps loosen any gunk or buildup on the knife. Use the toothbrush to scrub any hard-to-get places. Wipe off the excess (now dirty) oil with a towel and apply a drop of clean lubricant (WD-40 or light cooking oil) to the hinges. This method should remove the majority of dirt and grime and will not harm your knife in any way, but if you are still having problems, see methods 2 and 3.

Method 2: Boiling Water – A Very Thorough Knife Cleaning

You will need: Pot of boiling water, old toothbrush, tongs, clean towel, lubricating oil (such as WD-40 or light cooking oil) Warning: Only clean your knife using this method if it has no plastic parts or you can keep the plastic away from the boiling water.

To get started, unfold all the blades and tools on the pocket knife, multi-tool, or simple folding knife. Using tongs (so you don't burn or cut yourself), put the knife into the boiling water for about 45 seconds. Remove your knife using tongs, and set it on a clean, dry towel and allow it to cool off and dry. You can also carefully drain the boiling water and add warm (not cold) water to the pot to help speed the cooling process. If there is gunk built up on the knife that did not come off in the water, you can use an old toothbrush to scrape it off, but make sure not to actually touch the hot metal with your hand. Once the knife is dry, put a few drops of oil on the hinges (wipe off any excess) before closing all the blades of your tool and putting it away.

Method 3: Dishwasher – For Lazy Knife Cleaners

You will need: a Dishwasher and a dry towel

This is the least thorough and most damaging way to clean your knife, but for the short term, it definitely works. Make sure to use a mild dish detergent, and don't run the dry cycle. Simple remove your knife, dry it with a towel, and add some oil or lubricant on the hinges afterwards. There is a risk if you leave it in the dishwasher for too long afterwards that rust will build up, so make sure to remove it and dry it off promptly.