SANTOKU
SANTOKU
Updated August 2026 · 6 min read · UK Japanese knife specialists
The short answer
Stainless steel resists rust and staining, but it can still tarnish or spot if it is left wet or exposed to salt, harsh chemicals or acids. Regular cleaning and thorough drying prevent it — and restore it if it does happen.
“Stainless” does not mean stain-proof — it means stain-resistant. Stainless steel is any steel with at least around 10.5% chromium, which forms a thin, self-healing protective layer on the surface. That layer is what shrugs off most rust and staining, and it is why the same family of steels is used for everything from sinks to kitchen knives. But under the right conditions the surface can still dull, discolour or spot. Here is why, how to stop it, and how to keep your knives in particular looking their best.
Does stainless steel tarnish?
Yes — under certain conditions. Tarnishing shows up as a dull, discoloured or spotted surface, usually from prolonged exposure to air and moisture, mineral-heavy water, harsh chemicals, or the acids and oils on our skin. How much it happens depends on the grade of steel, the environment, and how it is cared for. Higher grades resist it better, and good habits prevent it almost entirely.
Kitchen knives use hardenable martensitic stainless steels — grades such as VG10, AUS-10 and 440C — chosen because they take and hold a keen edge. They are highly rust-resistant, but like any stainless they are happiest cleaned and dried rather than left wet.
What causes stainless steel to tarnish?
- Air and moisture left on the surface for long periods.
- Hard or mineral-rich water, which leaves spots as it dries.
- Harsh chemicals such as bleach or ammonia.
- Salt and acids — including citrus, tomato and the oils on your hands.
How to prevent stainless steel tarnishing
- Clean regularly with a soft cloth or sponge and mild detergent.
- Dry thoroughly straight after washing — don’t let items air-dry wet.
- Avoid harsh chemicals and abrasive scourers that scratch the surface.
- Store dry, and keep knives off acidic foods for long spells.
Our kitchen knives are forged from high-carbon stainless steels (VG10, AUS-10 and 440C) — keen and rust-resistant, but happiest hand-washed and dried. Keep yours bright:
Shop best-selling knives → How to remove rust →How to remove tarnish from stainless steel
If tarnish does appear, it usually lifts with a gentle home remedy:
- Vinegar and baking soda — make a paste, rub gently with a soft cloth, rinse and dry.
- Lemon juice and salt — the same method, useful for light spotting.
- A dedicated stainless-steel cleaner — follow the maker’s instructions, then rinse and dry.
Always rub along the grain, avoid abrasive pads, and dry fully afterwards. For a knife that has actually started to rust rather than just tarnish, see our rust-removal guide. If you want to understand the steel itself, our VG10 steel guide explains why these grades resist corrosion so well.
FAQ
Does stainless steel tarnish?
Yes, under certain conditions. It resists rust and staining, but salt, harsh chemicals, acids or prolonged moisture can dull or spot the surface. Regular cleaning and drying prevent it.
Do stainless steel kitchen knives rust?
They are highly rust-resistant but not fully rust-proof. Hand-wash and dry them promptly rather than leaving them wet, and they stay bright for years.
How do you prevent stainless steel tarnishing?
Clean regularly with a soft cloth and mild detergent, dry thoroughly, avoid harsh chemicals and abrasive scourers, and store items dry.
Can tarnished stainless steel be restored?
Yes. Mild home remedies such as a vinegar-and-baking-soda paste or lemon juice and salt, or a dedicated stainless cleaner, remove most tarnish. Rinse and dry afterwards.
Should you put stainless knives in the dishwasher?
No. Dishwasher heat, salts and detergents accelerate spotting and dulling. Hand-wash and dry knives to keep them bright and sharp.
Related guides
Sharp, rust-resistant and built to last — explore our Japanese-steel kitchen knives.
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