Knife Disposal

Did you know there's a proper way to dispose of knives? Don't just put them into the trash when you're done with them!

Because kitchen knives are cutting tools, they need a special way to be disposed of to keep yourself and others safe. Of course, we want to educate people on maintaining and keeping their knives for as long as possible - but eventually there is an end point. This article goes into details as to how to safely dispose of knives that can no longer be used.

How long can a knife be used for?

This is a question we see often, and it's rather rhetorical. There's no precise answer, but there is a simple one!

In short, the answer is "longer than you'd think." We often see knives that customers have brought in for disposal as they think the knives have reached the end of their journey, yet these knives are actually still very usable.

Basically, we define "usable" as being able to form a cutting edge on the knife.

As long as you can sharpen a knife to give it a cutting edge, the knife can still be used, so even the cheapest knives can actually last for a very long time. Even if the quality is not perfect, they can still be used.

Knives are meant to be generational. If cared for, they can last well over 30 to 40 years. We tend to look at end of life as the following:

The knife is no longer a knife when the steel runs out - or rather, when it can no longer be given an edge even after sharpening.

However, the structure of a knife differs depending on the type of knife that it is, so the amount of steel that is included will vary depending on the type of knife. For example, a larger, longer knife like a gyuto will have more steel than a small one like a petty knife. There's different steel structure styles as well, which can vastly affect a knife's lifespan.

All-Steel and Cladded Steel are the two main structures of steel one will normally encounter in completed kitchen knives. The diagram below gives a good example of the differences both in double-edged and single-edged blades.

All-Steel is precisely as it states, a knife made entirely of one type of steel.

Cladded steel is a harder steel cladded between other metals like soft iron or stainless steel. Cladded steel is a steel you need to be more discerning with when purchasing, which we'll explain shortly.

All-steel can be sharpened to any point, with the exception of honyaki knives. This is because while honyaki are made with a single steel material, the blade is heat treated to reduce the hardness of half of that blade during quenching/hardening, so the blade cannot be sharpened all the way.

Cladded steel can be further subcategorised into different styles, Warikomi Awase and San-mai Awase techniques. There are other techniques also, but for this example, let's just refer to these two. Refer to the diagram below for examples with double-edged knives.

With San-Mai, the hard steel goes all the way until the end of the blade, while with Warikomi the hard steel stops around half way. This is because generally, Warikomi knives have the hard steel inserted into a bed of split soft iron of sorts, which is then forge welded to that softer steel. As a result, it can't go the entire way through to the end of the knife.

For this reason, when you sharpen a Warikomi based knife down to roughly half of it's original size, it's effectively out of lifespan as there is no longer any hard steel to sharpen with. Be careful of this when buying knives so you don't accidentally purchase one that will run out faster. This is not to say such knives are a bad purchase, they simply will not last as long. Choose what is best for your needs.

Can I just throw the knife away?

Even knives that have been carefully used and sharpened will eventually reach the end of their useful life. They are a finite resource, even if it takes a long time for that to happen.

Most people probably don't pay much attention to it, but when it does come time it's easy to wonder "Just how do I throw a knife away?"

As it's a steel and often wooden structure, it can't just be thrown away with burnable trash in Japan, or perhaps where you are. It can't just be put into the trash can, that would be unfair to the tool that's supported you also.

So the main question is - just what do we do with knives that no longer have use? Here's a few tips.

Find out the rules of your local council

Each local government in Japan has clear rules about kitchen knife disposal, and there might well be the same where you are. So start off checking that on your local council's website or by contacting them.

Some governments classify kitchen knives and other cutlery with special disposal instructions.

Generally, they're not considered harmful from a disposal perspective and can simply be placed in non-burnable garbage, but the concern is garbage collectors themselves. In order to avoid injuring them accidentally, it's best to write on the trash bag that there is dangerous, sharp objects inside or kitchen knives so they know to exercise care when removing them. Also, consider putting them into some kind of wrapping or smaller box when throwing them away to prevent cutting the garbage bag and again for the safety of the collectors. Having them in their own garbage bag specifically also works.

Take it to a knife store

Knife stores still exist all throughout Japan and in many places elsewhere in the world. Some of them (not all) will dispose of your knives for you. Feel free to contact them ahead of time and check. It might come off as a little rude to bring a knife bought from another knife shop without checking first, so be sure to reach out ahead of time. There's a good chance they will not be against a customer coming in the door though, because if they're disposing a knife - they likely need a new one!

Hold a memorial service for your knife at a shrine or knife memorial festival

Sometimes knives live through people's lifetimes. When someone uses a knife every day, they can become attached to it. In effect, it's become a part of them. In Japan, there is much belief that items or things have "souls", so there is a culture here to hold memorial services for items of importance to a person such as dolls. This also applies to knives.

Infact, many knife-making regions hold festivals to allow people to perform knife memorial services.

The knife memorial festival held on November 8th in Seki City, Gifu Prefecture is especially famous.

Many local shrines also hold memorial services for knives and other cutlery.

Alternatively, send your knives you no longer use or your knives that you want to honor to us!

As knives are a huge part of our own souls and what we do, we also engage in many pratices that respect knifemaking, using and the entire lifespan and process. Knives used for years or even decades are filled with the thoughts of the craftspeople that made it, the love of the user that cut with it, and the ingredients they cut into. Due to this, we take that responsibility onto our own and hold knife memorial services upon request.

Contact us and send your knife to us with "Knife Disposal Service" written on the package, and we will handle the rest. A good time for this to save on shipping might be to send them at the same time you send a knife to us for sharpening. Or to send multiple knives at once.