Helle knives are designed to retain their sharpness as a lifelong outdoors companion. But it is still important to take care of your knife and its sheath.
The Handle: Dry the handle with a soft cloth if wet and wax occasionally.
The Sheath: The leather needs to be impregnated occasionally with colourless impregnation agent (grease or wax) to keep supple. Dry the sheath carefully in room temperature if it becomes wet.
The Blade: Wipe the blade with a soft cloth if wet and treat with grease occasionally.
Use a diamond tool or a wet stone for sharpening. Place the knife bevel flat to the sharpening tool and work the entire blade. Work one side until you can feel a slight burr on the opposite side.
Switch side and repeat the procedure until you feel the burr on the first side. You have now established an edge.
Remove the burr by stroking the blade gently over the sharpening surface on both sides, as if cutting very thin slices. Keep the bevel flat towards the sharpener and move from side to side until the burr is gone.
If the blade is very dull or damaged, use a fine-grained grindstone and plenty of water and sharpen until you have a raw edge. Use much cooling liquid and never sharpen on a dry stone. A hot-ground edge looses its heat treatment and ruins the blade.