Introduction: Removing Rust With Citric Acid

Picture of Removing Rust With Citric Acid
This is one of the easiest, safest, and least abrasive ways to remove surface rust from old steel tools.

  • Citric Acid Powder  (available at drug stores or grocery stores as a health food supplement or a baking ingredient)
  • Warm Water
  • Container
  • Scouring Pad / Brass Brush
  • Rusty Parts
  • Rubber gloves are a good idea
  • Don't splash it in your eyes
  • Do a test before trying this on something important - I've noticed it caused a swan chisel to turn very slightly yellow.
  • Do not try this on something like a saw blade with an etching you want to preserve - it might disappear.
Other Ways to Remove Rust:
Wire Wheel on a Grinder - this is probably the quickest way to remove rust, but it's still abrasive, so be careful around logos you want to keep.
Electrolysis - works well, but you have to be careful with batteries and water. not for the novice.
Sandblasting - very quick, but can leave a rough finish depending on the media. requires masking on painted parts.
Sanding - tedious and dirty and removes metal, but it works. sanding in very tight places can be impossible.

Advantages to using Citric Acid:
  • Does not remove painted finishes.
  • Less messy.
  • Requires nothing you don't already have in the kitchen.
  • Can be poured down the sink (citric acid is the main ingredient of some biodegradable cleaners).
  • Way cheaper than sandpaper.

Step 1: Clean the Parts

Picture of Clean the Parts
The rust on this wood plane wasn't too bad. The chip breaker was the worst part, but it was mostly just thick surface rust.
  • The first step is to clean off any dirt with water and a sponge.

Step 2: Prepare the Solution

Picture of Prepare the Solution
  • Find a container that is large enough for the parts to lay down flat. This way you only need to cover them with a shallow pool of water.
  • Place the parts in the container and cover them with warm water.
  • Add the citric acid powder and stir it in. Experiment with the proportions here. I used probably a 1/2 ounce of citric acid with 15 ounces of water.

Step 3: Wait, Scrub, Wait, Scrub

Picture of Wait, Scrub, Wait, Scrub
  • After a few minutes small air bubbles will form on the part from the chemical reaction.
  • After 30 minutes or 1 hour you may see flakes of rust in the solution.
  • Scrubbing the parts with a scouring pad or brass brush will speed things up.
  • There will be a black haze on the part, but it will scrub away.
  • The blade and most of the screws were ready to come out after 1 1/2 hours.
  • Add more citric acid to the solution if needed.
  • Wait, scrub, wait, scrub until the rust is gone.
I left the chip breaker in for 7 hours with no damage. A very lightly rusted part should be rust free after 30 minutes and some scrubbing. A moderately rusty part only needs 2-4 hours depending on how often you scrub it.

The solution can be poured down the sink when you're finished.

Step 4: Oil the Parts

Picture of Oil the Parts
  • After removing the parts from the solution, rinse them off with water and dry them thoroughly.
  • Oil everything or the rust will reappear when the parts get wet. I used camelia oil, made for rust prevention, but any oil is better than nothing.
What's really nice about this process is that the rust is removed even in hard to reach places, and it helps preserve the original markings without over-restoring the part. The finish is a little bit dull straight out of the acid, but can easily be shined up with fine steel wool or fine sandpaper.

Step 5: Before / After

Picture of Before / After

The before and after results are pretty dramatic considering how little you need to scrub the parts.

I wanted to share it here because it would have saved me countless hours of sanding over the years!


Eagleman117 (author)2017-09-08


andrew.mead.1253 (author)2015-05-14

The photograph of the two angles says it all concerning the finish. I cannot help but notice what appears to be significant shrinkage of the treated angle; it's now about 1/3 smaller than the untreated angle.

Citric acid doesn't shrink metal. That's silly.

The first image of the two squares is a photoshop, there is only one square. I put two pictures together, so any size difference you see is because of that. Nowhere near 1/3rd smaller though.

I forgot I wrote that. I kill me! (never mind). Good instructible but I admit having trouble and no luck finding citric acid in retail stores. I know of a pharmacy that compounds chemicals and medicines--surely they'd have citric acid as I have a use for some gentle rust removal in a safe compound like citric acid and water. Pax!

use cola instead

3of5 (author)andrew.mead.12532016-01-21

Concentrated Lemon Juice does very nicely, just don't dilute it too much, or even at all. You can find it at any food store as it is commonly used in stuff needing.... lemon juice.

Anywhere that sells supplies for canning fruits, jam/jelly, etc. -- things like mason jars & lids, labels, canning funnels.... will have citric acid. Hardware stores that have a good selection often carry this stuff -- call around to your local Ace or TruValue franchise, maybe Target or WalMart.

Try a health food or GNC store. Some Michaels and Hobby Lobby stores also carry it.

The cheapest place I've found citric acid is the Indian grocery store, it's with the spices. A good grocery store should sell it as well.

rfmonaco (author)2017-03-14

Amazing process! Thanks for the hints.

HybVigor (author)2016-08-25

Great Demo! For small items, using this technique in a ultrasonic cleaner speeds the process
dramatically. I place the citric acid solution in a secondary plastic
container with your parts and surround that with warm water in the cleaner. Monitor so as to not go too long. This works great for brass parts as well.

svigness (author)2016-08-22


afarrakhov (author)2015-05-15

Vinegar can be used to remove a rust too.

3of5 (author)afarrakhov2016-01-21

Not as fast a citric acid (I speak from exirience), but it gets the job done.

Namirreh (author)2015-05-14


You could even use WD-40(a rust inhibitor) as a buffing agent.

rf (author)Namirreh2015-05-15

WD-40 eventually causes rust since it contains alcohol which attracts moisture.

lionsden (author)rf2015-05-17

Just looked at a can of WD40 I happen to have in the shop. There is no alcohol listed, plus it is described as "drives out moisture" hence the name "WD40" where "WD" stands for "water displacement". It is also called "flammable" because of the propellant used but once it is out of the can and on a surface I have NEVER seen it burn (in fact my son just tried to light a small puddle of the stuff to see what happens. - nothing.)

lionsden (author)lionsden2015-05-17

Further checking shows "petroleum distillates" which are flammable.

3of5 (author)lionsden2016-01-21

I know it contains petroleum products, I used it to start an engine. It's also good for flooded engines.

3of5 (author)lionsden2016-01-21

I know it contains petroleum products, I used it to start an engine. It's also good for flooded engines.

LDM1 (author)rf2015-05-17

WD-40 was designed to evaporate h2o, that's what the WD stands for, water displacement and it took 40 tries before it was perfected : hence WD-40, just a little history. Happy tinkering!

Namirreh (author)rf2015-05-15

That shouldn't be a problem, the stove would/should be washed off after, or it will smell,so what ever it's washed with(dish soap,citric acid etc.)would remove all residual film left.If it is stainless steel, it won't rust unless you remove the finish

VendicarD (author)2015-05-16

How can I conveniently remove flesh from bone without producing anything detectable by the neighbors?

MartinB16 (author)VendicarD2015-10-25

use beetle larvae

CEVMarauder (author)VendicarD2015-05-16

Buy a large fish tank, some hamster bedding, a colony of Dermestid beetles, and a bunch of air fresheners?

AnnaB264 (author)CEVMarauder2015-09-10

Hmmm, may require lots of cutting to fit the pieces in the fish tank.... depending on how much you have to de-flesh, of course. Perhaps you could find an instructable on making a saw out of wood, so the evidence (I mean, tool) would biodegrade.

VendicarD (author)CEVMarauder2015-05-17


CatherineG (author)VendicarD2015-05-17

Boil it for a long time in a large pot. I do 2 chickens in a large show cooker for 10 hours to make delicious chicken broth.

ferjanyen (author)2013-12-29

There is a product call Ferricloride, you get it from any good boat chandlers. Takes rust marks from any thing inc. stainless steel. Good luck.

starphire (author)ferjanyen2015-05-18

Ferric chloride will eat into the exposed surface of the metal one is trying to restore if you let it soak for very long (it's often used to etch copper PC boards, and probably cheaper at an electronics store than a boat supply store given their markets). I would use it with caution for restoring old steel items, and definitely not if there are etched designs to be preserved in the metal being restored. Also, it will stain fabrics, wood, etc. if it drips onto them by accident, and rubber gloves (and non-metallic containers!) should definitely be used if soaking/etching items in it. It is also not a good idea to pour it down drains!

Ninzerbean (author)starphire2015-06-22

If you neutralize it with baking soda it is actually safe to pour down the drain.

wolfgang64 (author)ferjanyen2013-12-29

Ferric cloride is no joke. If you use it you have to agitate the bubbles it makes away from what you are working on or your results will be uneven. I work as a gun engraver and have used it a lot. Once accidently left small puddle of this stuff on a 16 gauge peace of sheet steel overnight in the morning it had eaten right through. It seems to work more agresively on metal that has not been work hardened.

bettina-sisr (author)2015-05-20

As a metal worker and environmentalist I try to use the least harmful stuff to complete a task, and I have found that to remove rust there are 2 more ideas that work wonders. First is Molasses! Yes Molasses. The ratio is 10 (water) to 1 (molasses) but I have found you can use a LOT more water. You just need a container big enough for your metal to be submerged, and time, it can take days, to weeks. There will be a molasses smell during, and funky foam will form (hmm?) in the shape of the metal on the surface (kinda cool actually) The second is Vinegar, and again the ratio is different for everyone, from 100% to 10:1, experiment for yourself to find what works. I think the vinegar is a lot like citric acid in why it works. GREAT INST!!

sketchglass (author)bettina-sisr2015-06-14

Hej bettina, thanks for sharing. never would have thought to try molasses!

sbrittain3 (author)2015-05-18

Catherine I will look for you a fb page post a pic of your car. Mine is Wimbledon white. I have posts on there you should be able to find me. Look forward to seeing your car. :)

sbrittain3 (author)2015-05-15

Bumpers? I have some light surface rust on my 65 Fairlane safe to use on them?

CatherineG (author)sbrittain32015-05-17

I just inherited my Grandpa's '65 Fairlane 500 Sport Coupe from my Dad. Where do you get parts? I'll need a few.

sbrittain3 (author)CatherineG2015-05-18

Hello Catherine welcome to the wonderful world of owning a Fairlane. Sports coupe awesome. The first thing I would do is join Fairlane Club of America. If on Facebook join the Fairlane group. You will find a ton of info from booth. The Fairlane club site has parts for sale and there is a good chance you will find what you need cheap. I also go to for parts they even have some of the accessories for our year. If there is a way I can message you I will send my email so you can ask me for help anytime. One thing I love about the 65 is we are a rare car at car shows and cruisenights so we get alot of attention. :)

CatherineG (author)sbrittain32015-05-18

Wow, thank you so much. I'm going to join the fb group now and hit up the club after work. I'm so looking forward to driving this car again. It's what i drove in high school in the early 80s.

MrJanuary (author)sbrittain32015-05-17

diet coke for bumpers or anything chrome for that matter.

sbrittain3 (author)MrJanuary2015-05-17

Thank you Mr. January.....

shawnlambert (author)2015-05-17

Thanks for this Instrucable... I like a solution I pour down the drain without destroying the environment. Great post.

rolandcontreras (author)2015-05-15

It is a nice instructable. Using citric acid has two effects, it has a low pH (high acidity) but also a complex forming activity with iron. So, don't use it for too long on your equipments, or they will disappear. It is present in high amounts in lemons, but it is rather cheap in some stores (drogist?).

PetraP1 (author)2015-05-15

Just brush it on.

PetraP1 (author)2015-05-15

Brush it on.

ljhtg (author)2015-05-15

Fantastic, can't wait to try this out! Thanks for posting.

jeffcole (author)2015-05-15

What a good idea. An old timer once told me you could also use molasses to achieve rust removal, but it tends to smell a bit. This way seems easier.

Thanks for sharing.

Deltic (author)2015-05-14

You can't beat the old methods! For larger items that are too big to soak mix a paste using lemon juice (i.e. citric acid) & salt. Spread on surface, leave for a while then rub with a cloth & plenty of elbow grease. Rinse & repeat as necessary. Once cleaned up protect with oil or a couple of coats of clear auto lacquer.

M2aestro (author)Deltic2015-05-14

Careful with your mix of citric acid and salt, not from a personal safety aspect, but because residual salt on the parts accelerates rusting.

jspence1 (author)2015-05-14

Do you think this would remove bluing from a firearm?

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