From the manufacturer
Care Tips for Swiss Army Knives
The various tools are manufactured from high-quality steel with precisely tuned features that are essential for the particular application. The steel is tempered, annealed and polished to achieve the necessary hardness and provide optimum resistance to corrosion.
To re-sharpen your knife, use a whetstone at an angle of 15°– 20°. This will result in a cutting angle of 30°– 40°. If sharpening on a grinding wheel, always cool with plenty of water to avoid excessive temperatures and the resulting damages that may occur.
After you’ve used your Swiss army knife for all of its various applications, such as cutting open numerous boxes, you may notice that the blades are sticking together. Open and close the blades in warm water several times and the tools can be easily moved again. When they have dried it would be good, but not always necessary, to apply a small drop of oil between the blade or tool shank and the spring. On the locking mechanism sometimes a drop of our recommended Swiss army knife oil could be helpful. Never put Swiss army knives in the dishwasher!
Swiss Army Knife Oil (Victorinox Part. No: 4.3301)
The main features of this multi-purpose oil are:
(1) Neutral odor and taste, (2) Highly resistant to aging, (3) Good wear and corrosion protection qualities, and (4) Food safe.