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Rust Erasers for Carbon-Steel Knives

Published March 2015

How we tested

Rust erasers, made from a rubber compound surrounded by a medium- or fine-grit abrasive, are designed to rub away the unsightly corrosion that can build up on and damage carbon-steel knives by removing small amounts of the rusted metal from the surface. (Rust should not be confused with patina, a beneficial form of oxidation that affects only the outer surface of the metal, turning it charcoal-gray and protecting it against rust.) You simply lubricate the eraser’s surface with water and rub it gently along the knife’s blade with the grain (these products can leave scratches, so it’s best to move back and forth in the same direction while following the metal’s grain). We tested two models (priced at $5.73 and $7.29), both medium-grit (the style sold by most companies; experts told us that the scratch pattern it leaves behind most closely resembles the existing grain of most carbon-steel knives). We let new carbon-steel knives air dry and develop rust, scrubbed them, and repeated the process three times. We also let three additional new carbon-steel knives rust and compared the erasers with more common household products: medium-grit sandpaper, metal polish, and a mild kitchen cleansing powder.

All five products removed rust effectively after just 3 to 4 minutes of gentle scrubbing per side. However, they revealed black marks where the rust had been that indicated “pitting corrosion”—that is, tiny holes where the corroded metal was removed. Fortunately, a knife expert reassured us that the tiny pits won’t weaken the strength of the blade as long as it doesn’t rust further and require more erasing that would remove more metal.

Ultimately, we preferred the dedicated erasers for their ease of use. The polish and the powder required us to dirty kitchen towels to scrub them into the metal surface, while the sandpaper was slightly less nimble and difficult to maneuver on the knife’s sharp corners. Of the two erasers, one model proved exceptionally durable, remaining coarse and sturdy after repeated scrubbing on sharp edges and tight corners, while another crumbled and its abrasive grit wore down. Though we’re always careful to thoroughly dry our carbon-steel knives so that they won’t rust, we’ll keep the erasers on hand for emergencies.

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The Results


Design Trifecta 360 Knife Block

Admittedly expensive, this handsome block certainly seemed to live up to its billing as “the last knife block you ever have to buy.” The heaviest model in our testing, this block was ultrastable, and its durable bamboo exterior was a breeze to clean. Well-placed medium-strength magnets made it easy to attach all our knives, and a rotating base gave us quick access to them. One tiny quibble: The blade of our 12-inch slicing knife stuck out a little.


Schmidt Brothers Downtown Block

This roomy block completely sheathed our entire winning knife set using just one of its two sides—and quite securely, thanks to long, medium-strength magnet bars. Heavy, with a grippy base, this block was very stable. An acrylic guard made this model extra-safe but also made it a little trickier to insert knives and to clean; the wood block itself showed some minor cosmetic scratching during use.


Schmidt Brothers Midtown Block

This smaller version of the Downtown Block secured all our knives nicely, though the blade of the slicing knife stuck out a bit. With a base lined with grippy material, this block was very stable. An acrylic guard afforded extra protection against contact with blades but made it a little harder to insert knives and to clean; the wood itself got a little scratched during use.

Recommended with Reservations

Swissmar Bamboo Magnetic Knife Block

This small, scratch-resistant model had a stable, rubber-lined base and could hold all our knives, though the blade of the 12-inch slicing knife stuck out a bit. But inch-long gaps between its small magnets made coverage uneven and forced us to find the magnetic hot spots in order to secure the knives. Its acrylic guard made it safer to use but harder to insert knives and to clean.

Not Recommended

Messermeister Walnut Magnet Block

This handsome block was done in by its shape—a tippy, top-heavy quarter-circle that wasn’t tall or broad enough to keep the blades of three knives from poking out. It lacked a nonslip base, and its extra-strong magnets made it unnerving to attach or remove our heavy cleaver. Finally, it got a bit scratched after extensive use.


Epicurean Standing Knife Rack 12"

This magnetic block sheathed all our knives completely, though with a bit of crowding. But it was hard to insert each knife without hitting the block’s decorative slats on way down, and because the block was light and narrow, it wobbled when bumped. Worse, we couldn’t take it apart, so splatters that hit the interior were there to stay. Additionally, the outside stained easily, and when we wiped it down, the unit smelled like wet dog.


Kapoosh Rondelle Knife Block

This model stabilized knives with a mass of stiff, spaghetti-like bristles that shed and nicked easily after extensive use, covering our knives with plastic debris. While all our knives fit securely, several of the blades stuck out, making this unit feel less safe overall. Finally, though the bristles could be removed and cleaned in the dishwasher, their nooks and crannies made this block hard to wash by hand.


Kuhn Rikon Vision Knife Block, Clear

This plastic block required us to aim each knife into the folds of an accordion-pleated insert that was removable for easy cleaning but got nicked easily with repeated use. Because we could only insert the knives vertically, longer knife blades stuck out; a cleaver was too wide to fit. The lightest model in our lineup, this block was dangerously top-heavy when loaded with knives.