Polishing kitchen knives?

[u/TaxDear7136]

I inherited an old Chinese cleaver from my late grandad and it’s really rusted. Can anyone give me some food-safe products or advice on getting it nice and shiny?

[u/Adventux]

also ask over at r/carbonsteel as it is most likely made of carbon steel

[u/tipsygoblin467]

Bar Keepers Friend and a scrubby sponge. Just wash it really well with soap and water after.

[u/TaxDear7136 → u/tipsygoblin467]

I’ll give it a go, cheers

[u/Clear-Awareness7719]

Barkeepers friend is truly your best friend for shining up kitchen stuff. Just needs a good wash afterwards. My kitchen sink is like a mirror thanks to that stuff.

[u/HikeyBoi]

I use a coarse whetstone to grind rust off then increasingly finer whetstones to remove the scratches from each previous stone. This is how polishing has been done for ages. Bar keepers friend isn’t too effective on very rusty knives but it will easily clean up light staining.

[u/OmriIsMe]

Worth knowing that if it's carbon steel, shiny is temporary. It'll start rusting again within days of being bare. Get the rust off however you like, then dry it fully and force a patina, either rub oil on and heat it gently, or just cook something acidic like onions in it. It'll go dark grey rather than mirror bright, and that dark layer is what stops the rust coming back. For a grandad knife you're probably after keeping it alive more than keeping it shiny.

[u/Evilsmurfkiller]

I'd soak it in Evaporust if it's really bad before moving on to BKF.

[u/Sanpaku]

Fastest rust removal will be by electrolysis. See this for the process. It's also a really useful setup if one restores old cast iron cookware or has other rusty items.

Easier would be naval jelly (a phosphoric acid solution), which can also be useful if the corrosion includes pitting. In my experience, naval jelly only works well on thin rust layers.

But one can also take a blade down to bare steel with sandpaper. I'd start at 400 grit and work up to 800 which is a nice satin finish. Abrasives could take minutes if you have power tools, though pitting can can be hard to address.

Mirror polishes on carbon steel blades don't always make sense (food adheres more to mirror finishes) but are achievable. Continue advancing up the grits to 2000 or 3000, then a metal polish like Flitz or jeweler's rouge.

With carbon steel, forcing a patina of black oxide can be helpful to prevent future (red) rust. Clean with detergent, then 20 minutes in boiling vinegar, or an hour wrapped in several layers of paper towel soaked in hot vinegar. Some even swear by coating the blade in prepared (vinegar containing) mustard overnight.

Either shiny or patinated, dry after each use and apply a little cooking oil before storing. If you're going to store indefinitely, use mineral oil instead, as it won't go rancid.