Short answer: warm water, a drop of dish soap, an old toothbrush, then dry it completely and put one drop of oil on the pivot. Ten minutes, twice a year, and a folding knife lasts a lifetime. Never put one in a dishwasher.
What actually makes a folder stiff
It is almost never rust. It is pocket lint, dust and skin oil packing into the pivot and under the liners, then setting hard. That grit also acts like sandpaper every time you open the knife, which is what wears a pivot out.
The routine
1. Open it and lock it. Work on a knife that cannot close on your fingers.
2. Warm water, a drop of dish soap, an old toothbrush. Scrub the blade, the spine, and especially around the pivot and inside the handle scales. A wooden toothpick gets into the corners a brush cannot.
3. Rinse briefly. Do not soak it. Water sitting inside a handle overnight is how a carbon blade rusts from the inside.
4. Dry it completely. Cloth first, then leave it open somewhere warm for an hour. Compressed air, or a hairdryer on low, gets water out of the pivot faster.
5. One drop of oil on each pivot. One. Open and close the knife ten times to work it in, then wipe the outside dry. More oil does not mean smoother, it means a lint magnet.
6. Wipe the blade with an oiled cloth if it is carbon steel.
Handle materials need different care
| Micarta and G10 | Bulletproof. Scrub as hard as you like. |
| Wood | Quick wash, dry immediately, and a wipe of mineral oil a couple of times a year to stop it drying out and shrinking away from the bolsters. |
| Bone, stag, horn | Never soak. These absorb water, swell and crack. Damp cloth only. |
| Pearl and shell | Damp cloth, nothing abrasive, no solvent. It is a natural material and it scratches. |
| Brass bolsters | They will patina. That is normal. A metal polish brings the shine back if you want it. |
What not to do
No dishwasher. Heat, harsh detergent and steam will ruin wood and bone scales, dull the edge against the rack, and drive water into the pivot.
No WD-40 as a lubricant. It is a water displacer and it evaporates, leaving a sticky film that attracts grit. It is fine for flushing a seized pivot, but oil the knife properly afterwards.
Do not fully strip the knife unless you are comfortable reassembling it. Most folders can be cleaned perfectly without touching a screw, and a stripped pivot screw is a much bigger problem than a stiff action.
Questions people ask
How often?
A wipe and a drop of oil monthly for a carry knife. A proper clean twice a year, or immediately after it gets wet, salty or dirty.
Mine is already stiff and gritty
Flush the pivot with hot soapy water while working the blade open and closed, dry thoroughly, then oil. That fixes almost every stiff folder without any disassembly.
What oil should I use?
Depends whether the knife touches food. We wrote a full answer: which oil to use on a knife.
There are already rust spots
Easy to reverse if you catch it early. See how to remove rust from a knife.
More from the workshop
Which Oil to Use on a Knife
Mineral oil for food knives, machine oil for the rest, and never cooking oil.
How to Store Knives Properly
Contact and moisture are what ruin stored knives. Both are easy to avoid.
Butterfly Knife Tricks for Beginners
Start on a trainer, get smooth before fast, and learn the close before the open.