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topic 17903

Tile contractor's muriatic acid corroded our stainless steel appliances

A discussion started in 2002 but continuing through 2017


Q. Our general contractor recently used Muriatic Acid and water to clean the tile floor. All the stainless steel cooking appliances in the room have developed a sticky brownish layer of corrosion, even the overhead exhaust hood which could only have come in contact with the fumes.

My Question: Is there any way to stop the reaction (neutralize the acid) in the area? Is it likely that the fumes are still escaping from the tile floor? I fear that the fumes may also attack the HVAC equipment in the area. My kitchen equipment supplier says the corrosion will continue to come back indefinitely unless repeatedly protected by a thin layer of oil.

Any experience with this type situation or suggestions are welcomed.

Harry Wilfong
- Hartsville, South Carolina


Q. I am having the same problem and have not been able to get answers from my contractor. Has anyone come up with a solution?

Ken Campbell
- Lake Placid, Florida, USA


A. I can't comment on your particular situation, sight unseen. But I would never let a contractor apply hydrochloric acid inside my house, and would suggest that it is very likely to be the cause of the rusting of the stainless steel. Eventually the fumes will dissipate, but I suppose that washing things with baking soda [linked by editor to product info at Amazon] would be useful if the acid application was recent.

I have done ceramic and porcelain tiling many times, and what happens is this: after sponging the grout across the tiles and into the grout lines, you must sponge wipe the tile again & again & again (and several more agains), emptying and refilling the rinse bucket again & again & again to get the haze off while it's still wet. And just when you think you're done, the sponge touches the grout line and drags a bit a grout onto the tile, and away we go again.

If you do this there is absolutely no need for acid! But it's a huge lot of labor, and time is money. So professionals often give it a couple of quick passes, and allow a grout haze to remain on the tile, which they remove with acid after it has dried. This may not be too bad if they use a "safe" acid, but muriatic acid is not a liquid acid, it's a gas dissolved in water like the fizzing very mild acid in Coke or Pepsi ... and as the acid is sloshed around, the gas fumes come out and ruin metal without having to have liquid touch it. Your appliances may be ruined. What you are seeing on the outside is probably affecting the wiring and electronics as well.

Ted Mooney, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey

December 11, 2012

A. When I use hydrochloric (muriatic) acid, I have simply used a baking soda solution to neutralize excess acid. Don't know if will work in your case but I would try mixing a solution of 3/4 to 1 cup of baking soda with a gallon of water and scrub the affected areas with it. Should do the trick. Good Luck

Charles Ogden
- Poplar Bluff, Missouri USA

March 22, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I also used muriatic acid on my kitchen floor and it ruined all of my stainless cookware that was hanging on a pot rack mounted on the ceiling. It looks like the worst kind of water spots. It also had an effect on the range.

Can I reverse the damage to the stainless as it is not etched, just discolored with white spots. I tried vinegar and it didn't help. I am also worried about inhaling the fumes.

Lily Benson
- Biloxi, Mississippi, USA

March 27, 2013

A. Hi Lily. Charles' suggestion of a baking soda wash is probably the best idea.

Acid fumes are clearly not good for you, but they have probably largely dissipated by now, and the baking soda might help even further. Some people work in plating shops with very strong muriatic acid every day and survive it just fine; I am not claiming the fumes are utterly harmless, I'm just saying that considering the ever-present dangers in life, if you weren't hurt at the time, there is no need to obsess about this very diluted issue. Good luck,


Ted Mooney,
Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey

March 16, 2016

!! My cleaning partner and I recently used a product called "BeatsAll Tile & Grout Cleaner" marked "CAUSTIC" and "unsafe for all metal" to clean the tile in an entire new house (no ingredients listed). As directed on the label, we applied it carefully to the tile without splashing (spilling, not spraying), scrubbed it with the special applicator brush (essentially a long-handled scrub-brush, made in Italy) and rinsed with warm soapy water. Next day, there were unsightly spots on 3 new kitchen appliances (stainless steel isn't un-stainable, it turns out!) and a hazy orange "rust" over the entire surfaces of all exposed stainless except the kitchen faucet. (Maybe that was pewter finish?)

Mothers Polish

We used every product we had in our attempt to remove the spots, including metal cleaners, with limited results.

The company returned my call for help and suggested "Mother's Mag and Metal Polish" from an auto supply store. They said that would remove the stains and they would not return. We found "Mother's Mag and Aluminum Polish". It's a paste type, I think.

Unfortunately I don't have the rest of the story yet.

The owner likes the idea of getting the skins (front decor panels) of the appliances replaced. (Ouch, my purse. But probably cheaper than new appliances! I didn't realize that was possible, until now.) Lesson learned: don't let messy tile guys leave without cleaning first! Caustic substances are no joke.

Victory Dove
- Port Charlotte, Florida

April 2016

A. Hi Victory. According to the label, that tile cleaner contains inhibited hydrochloric acid. Inhibited or not, I would not use it in my house. I think there's a good chance that the Mother's Polish can remove the corrosion because it's a polish, not just a chemical reagent. But you may find that you need to use it on a buffing wheel in a low-power battery operated drill, or with a buffing pad on a hand-held orbital sander because it's hard to get enough "oomph" with your hands alone.


pic of Ted Mooney
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"

May 12, 2016

thumbs up signSo glad we found this site. The contractor cleaning our natural stone with some sort of acid left a streak down the front of our outdoor refrigerator and splatters on the other grill doors. We first washed it down with baking soda as someone recommended to neutralize the acid. We them bought the Mother's Mag and Metal polish and used buffing pads on an electric drill. Very happy with the outcome. One would have to know where the streak was to see an indication of it. Thanks everyone.

James Bearden
- Franklin, Tennessee USA

April 6, 2016

I hear this story all the time.

An abrasive/polish product will remove the corrosion, yes, but the best thing is to repassivate too.

We offer products that will clean up the corrosion (usually with no scrubbing required) and passivate at the same time.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
stellar solutions banner

April 8, 2016

Q. "passivate"
v.t. -vated, -vating.
1. to treat (a metal) to render the surface less reactive chemically.

Citation: Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.

Both replies add excellent info. I just had to look up this new word and thought I'd share it for others' convenience. :-)

I don't know where you read the ingredients, my bottle didn't specify... (I assumed the company didn't have to list because it wasn't food), but it's good to know. I wonder what the difference is between inhibited and uninhibited hydrochloric acid or HCl (a.k.a. muriatic acid, according to another post in this thread). I'm no chemist, but I know HCl (stomach acid) burns skin and leaves a "birthmark"-type pink stain as a permanent scar. My brother had an unfortunate accident that marked his tummy with a 2" spot. I think it's unfortunate this stuff isn't warned better. Caveat Emptor (let the buyer beware), I suppose.

Victory Dove
- Port Charlotte, Florida

April 2016

A. Hi again, Victory. Unfortunately your dictionary citation didn't translate completely because accent marks, pronunciation hints, etc. on keyboards are not accepted correctly by e-mail and HTML. Also, although your definition of 'passivate' is correct, it additionally has a rather specialized and reserved meaning when applied to a specific process for stainless steel.

I think we have a similar issue of a specialized and reserved meaning for the word "inhibited" when applied to a pickling acid, like hydrochloric acid. It means that special organic compounds have been added to help the acid dissolve rust in favor of steel.

We obviously don't know the formulation of such proprietary products, including whether there is a lot of HCl in it or only the faintest wisp; but my own experience from seeing the corrosion damage in plating shops, and from posting many stories of damage from HCl-based grout cleaners, is that I would never use any HCl in my own home. Others may see it differently; the product does have largely favorable reviews on Amazon.


pic of Ted Mooney
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"

June 29, 2016

Hello Victory. As your name implies, you don't settle for less than Victory!

Therefore to remove that stain you can and will obtain Victory with using Scratch-B-Gone on those stains. Used by grout and tile contractors nationally, our kit is very effective to lift this discoloration while restoring finish. Good Results Ahead.

Barry Feinman

Barry Feinman
supporting advertiser
Carlsbad, California

February 18, 2017

Q. We recently put new floors in the house and our installer used diluted muriatic acid to eat up the dust from the floors after installation was complete. He says he applied the diluted acid with a sponge, then wiped it immediately with water afterwards. 6 days later, I am realizing our stainless steel appliances are corroding ... every time I wipe them, they wipe brown.


What can we do to fix this?


August 4, 2017

A. I have a 2000 square foot rental home with tile and extremely dingy grout. I used muriatic acid throughout to clean grout. I have stainless steel appliances. I used "ZEP acidic toilet bowl cleaner" to remove residue. Wipe on, wait 5 minutes, used elbow grease to work it out. Rinsed thoroughly (or it will rust) with water. Then polished with stainless steel appliance polish. Appliances came out good as new. Problem solved. Try it first in a small area to test for sure.

Joni Pintado
- Vero Beach, Florida

August 2017

!! Hi. As Joni says, try it on a small test area first. Even if you rinse it well and polish it, I find it hard to believe that a toilet bowl cleaner which itself reportedly contains 10% muriatic acid is good for stainless steel.


pic of Ted Mooney
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"

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