Knife Care
To take care of your knife it is good to first know a few things about your knife...
(1) What steel is used in the knife? Different steels have different properties.
(1a) Stainless steels are usually a bit harder than carbon steels and this more brittle and more prone to chipping, they can be harder to sharpen, but will hold an edge longer and they are more resistant to stains and rust. Stainless stands for (STAIN - LESS). It is not completely impervious to rust etc and should still be taken care of... even lightly oiled now and then.
(1b) Carbon steels are more prone to rust. To keep things simple... If you have a Damascus knife treat it the same as you would a carbon knife. Carbon steel knives can offer great service if they are properly cared for. They are strong, easy to sharpen and for the most part less expensive than Stainless. They are however very prone to stain and rust. Acidic thing like tomatoes will stain carbon blades and create a patina. They should not be left wet. They should not be stored in their sheaths. You should clean and oil them after use.
(2) What handle material is used on your knife?
(2a) Lets start with bolsters and pins... Stainless is easy to care for, just use a soft cloth as it can still scratch. Brass should be kept clean as acids from the leather sheath could oxidize it and turn it green.
(2b) Synthetic handles like G10, Micarta, Kirinite requires little care. For the most part they are acid resistant, oil resistant, water resistant with little or no swelling or shrinking. Some but not all are also high impact resistant.
(2c) Stabilized wood is a good way to go to still get the natural look of wood, but without the big risk of cracking, shrinking, swelling etc.
(2d) Natural wood has been used for many years as handle material. It does however not like moisture and can shrink, swell or crack. Keeping it oiled can go a long way towards preserving your handle for many many years. The oil you use can also make a difference to the feel, finish and protection of the wood. Some oils are better suited for some wood than other. I personally prefer Burmese Teak oil as it absorbs deep into the wood, dries fast, does not get or feel tacky or oily afterwards. Is easy and cheap to come by and cleans easily off the bolsters and blade without leaving a waxy sticky layer.
(2e) Bone, Antler and Ivory. These materials are hard and can crack. Do not drop them! Keep them clean and in a stable environment. They can turn yellow over time.
(3) What is your sheath made of?
(3a) Nylon sheaths requires very little to no maintenance. They are cheap and flexible so careful not to pierce the sidewall with the tip of the knife.
(3b) Kydex sheaths are more sturdy. The can crack especially by rivet holes when dropped. The are harder wearing on certain blade finishes and can scratch blades, even more so if sand gets inside.
(3c) Leather sheaths are very traditional and durable. They can however stain blades and brass bolsters from the chemicals left behind from the tanning process. Do not store blades in leather sheaths, only carry them in it. Take care when inserting a knife in a leather sheath not to cut the sides or pierce the tip through the sidewall. If the sheath has a retaining strap, make sure not to cut it especially when pulling the knife out. Most leather sheaths have some form of pattern, stamping or carving on it. Do not put heavy object on top of the sheath and do not let it get wet. Do not oil your sheath.
(4a) DO NOT put your hand made knife in the dishwasher!!!
(4b) Do not use it as a screwdriver or pry-bar.
(4c) The handle or back of the blade is not a hammer!
(4d) Do not use a cheap sharpener. Use a diamond stone, oil stone, sharpening rod or professional sharpening kit. If you don't know how, don't do it. Take it to someone who knows what they are doing, preferably to the maker himself if possible.