Do Not put a Martell knife in the dishwasher or soak in the sink! This will ruin any good knife.
Carbon Steel - As for cleaning or maintaining the look/finish of a carbon Martell knife as it comes to you - I wouldn't. I would instead use the knife and let it develop a patina naturally and enjoy the beauty as it develops over time. Some folks look at patina as ugly or dirty while I view patina as a record of the history of the knife’s use, plus it serves as a natural layer of oxidation that will help to protect the knife from rust formation, so try leaving it in place and see how you feel about.
If you use the knife often you will need to do nothing special - just wash with warm/hot water, immediately dry, and store. If you infrequently use the knife, maybe only once in every few months, then I suggest coating it with camellia oil between uses, this will keep the rust at bay.
*A nice tip I can give regarding the forming of a base patina is to sacrifice an onion which will turn the knife brown/golden mottled - wash/dry - then cut some cooked beef and give the warm juices a minute to do their thing before rinsing off. The beef will turn the blade blue/purple which is very beautiful. Raw beef and chicken can add some level of blue to the blade as well as fish. You'll see a basic pattern form that will pretty much stay put unless you do something nutty like cut 40lbs of tomatoes or something like that as that'll wipe away some of the formed patina.
Stainless Steel - follow the above directions for cleaning/drying, but skip the oil.
In most cases we use exotic hardwoods that have been stabilized to reduce movement/warpage/etc yet wood (as well as horn) is a natural product and can swell and/or shrink with temperature/moisture changes, this is to be expected. To help our wood handles remain intact we additionally treat them with a protective oil/varnish finish, similar to that applied to fine wood furniture. Scrubbing handles may result in premature wear to the finish and should be avoided.
SHARPENING & HONING
Martell knives have very thin edges sharpened somewhere in the neighborhood of 8-10 deg (per side). Our knives have the bevels set using water stones and then finish sharpened using belts so that our customers can easily find the bevel with no extra grinding work required. Martell knives are not knives that come with built in sharpening problems - they are ready to go to work right out of the box and ready to go to the stones when the time comes.
For in between sharpening sessions we suggest the use of a strop, be it a felt pad or leather pad, charged with a fine diamond compound.
*Note - If sharpening knives isn't your thing then that's OK since Martell knives come with FREE Lifetime Sharpening. Just send them in to us and we'll get them back to like new edges, you only need pay the shipping.
STORAGE & USE
How to store your knives is something that you'll have to decide for yourself - maybe a magnetic knife rack, a counter storage block, or even the supplied padded case will be fine but please don't throw one of our knives in a draw with other items and expect it not to be damaged as this won't be the case. Fine knives and junk drawers don't mix well.
We strongly recommend the use of an end grain wood cutting board/block.
Do not use Martell knives on bones or frozen foods. Care should be taken in use to ensure that the fine edge supplied is not chipped on hard food products or through the use of inexpensive cutting boards.If cared for properly your Martell Knives should last you for a lifetime.