Stainless steel rusting


How do you avoid rust on your stainless-steel cutlery?

Will my cutlery resist rust?


So you dropped a few hundred or more on that stainless steel cutlery set - do you really want to risk cleaning it in the dishwasher? Will it survive the wash? And if it says dishwasher-safe, why do you still get rust spots on some knife blades?

This guide explains just how stainless stainless steel is, and helps you understand how you can get the most out of your your new investment.

Here's a stainless-steel overview

'Stainless steel' is steel to which chrome has been added for rust resistance and often nickel for acid resistance. Top-quality stainless steel (18/10) contains 18% chrome and 10% nickel. It's generally more expensive - and brighter and whiter in colour - than lower-grade 13/0 stainless steel, which can look quite grey. And despite its name, most metal alloys used in cutlery make it stain-resistant rather than stainless.

While most forks and spoons have excellent corrosion resistance, knife blades tend to be made of harder steel that gives a lasting edge but is more likely to rust, eventually, from repeated washing in a dishwasher. The hints below can help you minimise this risk.

Tips to reduce rust

  • Acidic and salty food remnants on cutlery will stain it. Rinsing the pieces off before you put them in the dishwasher, especially if you don't run it immediately, will help avoid this.
  • Storing dirty cutlery in your dishwasher for days will stain it eventually.
  • Washed and wet cutlery in the dishwasher overnight will add to the chance of staining. Opening the door when the cycles finished will assist drying, or take it out and wipe it dry straight after the program finishes.
  • Over-packing the cutlery basket means staining. Use a grid (technically known as an anti-nesting grid), so items don't touch each other. It's important that stainless steel and silver-plated or copper items don't come into contact, as the chemical reaction with hot water and dishwashing detergent can cause discolouration.
  • Avoid putting wooden, plastic, bone, or china handles into the dishwasher, unless they're labelled dishwasher-safe. Don't pour dishwasher detergent directly onto cutlery. Silver-plated cutlery becomes permanently stained and stainless steel can pit within minutes.
  • Don't soak cutlery for long periods in soapy water, bleach solutions, or salt water.
  • Don't use abrasive cleaning aids.
  • Stains such as water marks can generally be wiped off easily from knife blades, and for more persistent rust stains, use a non-abrasive metal cleaning paste or liquid - one formulated for stainless steel, not a silver cleaner - if necessary.
  • For rainbow-like stains, use lemon juice. 

Experts generally recommend washing good-quality knives by hand. Apart from risking rust stains, their sharp edges can deteriorate in the dishwasher as they get bumped into other dishes, cutlery or against the rack, all of which can blunt the blades. And, of course, it's safer not to have sharp knives hidden in among all the rest of the cutlery.

Removing rust spots

Maybe you've got scratches in your cutlery and the strong bleaching agents from dishwasher detergent have stripped some of the chrome from your stainless steel. Rust spots have developed and you're worried that they'll spoil the look, or you might have safety concerns. A plastic scourer with a baking soda paste (a little water and soda) rubbed over the rust spot and then further rubbed by a paper towel should remove the rust spot.

Key things to remember when removing the rust spot - don't use a metal scourer, it'll strip more of the chrome. The same goes for abrasive powders, they'll also strip the chrome out of your cutlery. Stick with some gentle rubbing. Other suggestions are lemon juice to loosen the rust from the cutlery.


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