Practice Safety! How to use Vinegar for cleaning hardware.

The “hardware soup” method to cleaning hardware was trendy among furniture refinishers as an effective way to clean grimy hardware like knobs, hinges and other metal fixtures from vintage furniture.


The method involved boiling white vinegar, submerging the hardware into the solution, and letting it boil for 15 minutes. The results shared on social media were incredible, and everyone joined the bandwagon. Myself included!.


I didn’t question initially why my eyes and throat felt burning when this concoction bubbled away, leaving old hardware like new. 

Table of Contents

Why Boiling Vinegar is Dangerous.

When I started to question the safety implications of boiling vinegar, I was pulled into a rabbit hole of information online. White vinegar, when boiled, can release vapours that contain high concentrations of acetic acid.


Acetic acid is the main component of vinegar and gives it its acidic properties. Normally, vinegar contains only 5 to 8 per cent acetic acid compared to its volume. However, when you boil vinegar, the water element is boiled off, and the acetic acid is left in a more concentrated volume. 


When vinegar is boiled, the concentration of acetic acid vapours can reach unsafe levels. Breathing in these vapours can cause irritation to the lungs, respiratory system, and eyes. Individuals who suffer from asthma could experience even worse symptoms, and the youngest in our families will be more adversely affected.

Boiling vinegar

How to use Vinegar Safely to Clean Hardware

There is a safe way to continue using vinegar for cleaning your hardware. I only recommend this method, however, for the toughest cases: those pieces of hardware covered in paint, grime, and years of gunk. 

Dirty Brass Hardware with tarnish from use over the years
Brass Hardware before Cleaning

Proper Ventilation

Proper ventilation is one of the first steps to using vinegar for cleaning hardware. You want to ensure that any acetic acid that may be boiled off is ventilated outside.


With good ventilation, the concentration of vapours in your home should remain low and not cause harm. But be vigilant for any burning sensation in your eyes or throat. Should you suspect that your vinegar mixture is not ventilating correctly, immediately turn off your heat source and open all windows, etc. 

open window

Dilute Your Vinegar

Rather than use straight vinegar, dilute it with water. You will still get the same effects as straight vinegar, but it will take longer for the acetic acid to start boiling off.


I recommend diluting to a 1-to-1 mixture of vinegar and water for tough jobs. Consider even going with a 2-part water to 1-part vinegar mixture for less dirty pieces.  

Just Warm, Don't Boil

While you require heat for the vinegar and water mixture to start working, nothing says it requires the water to boil. When the mixture boils, the water boils off first, leaving dangerous concentrations of the acetic acid.


Simply warming up the mixture at medium temperatures will prevent the water from boiling off, and the heat will still do its magic. 

Use Safety Equipment

Always use safety equipment. Protect your eyes and skin. Wear gloves and eye protection. You are your greatest asset, so protect yourself.


I know and understand that sometimes, when in a rush, you can forget your safety equipment or think it will just take a moment and you will be careful. But at the end of the day, we need to protect ourselves. 


So take the time and prioritize your health. Those who love and care for you will thank you. 

Keep Little Ones out of the Area

Similar with the dangers of lead, acetic acid can effect those little ones in your environment worse then it may effect you. So, when you are cleaning your hardware, keep them out of the area.

Cleaned Brass Hardware, the tarnish has been removed
Brass Hardware after Cleaning

Other Options for Cleaning Hardware

While “Hardware Soup”is popular for quickly cleaning the toughest grime, there are other tools that can work just as quickly. I no longer use vinegar for cleaning hardware as I consider the risks not worth taking. My personal method of cleaning hardware is with Brasso (easily available in your local Dutch Grocery store)

clean hardware with brasso

As with all chemicals, taking all necessary health precautions is important. I dislike the smell of Brasso and wear a respirator and gloves when working with the product. 


​Brasso is as simple as wiping the product on with a soft cloth and wiping it off again. In challenging situations, I allow the Brasso to sit on the piece of hardware I am attempting to clean for a few minutes.


I then use an old toothbrush to scrub the hard-to-reach areas and wipe the mixture off with a clean cloth. In the worst-case situations, steel wool with Brasso will remove any old grime that wasn’t removable with a cloth or toothbrush. 


Finish with mild dish soap and lukewarm water to remove any Brasso residue and allow to dry. A wipe with a microfiber cloth will remove any water spots. 


Brasso is also a fan favourite for cleaning brass items. A quick, light cleaning will remove grime and the initial layers of tarnish while allowing the much-loved patina of real brass to remain. Just ensure that you don’t over scrub and work away all the patina. 

Another popular product for cleaning brass Hardware is Bar Keeper’s Friend. I have not personally tried the product as it is not as readily found in the Netherlands as Brasso. It works similarly to Brasso in that you must wipe it on with a clean, soft cloth. For tougher grime, you can allow it to sit for a few minutes. Rub the product off with a clean cloth and follow up with a soapy bath with a soft detergent to remove any product residue.

DIY Brass Cleaners

Salt and Lemon Juice for a natural cleaning solution for brass hardware

If you prefer to try more natural cleaning methods, there are a variety of cleaning solutions made with household products. These methods are simple and a natural way to clean any brass surface.

Salt Polish

To make your salt polish, mix lemon juice and salt in equal parts. This will create a paste. First, clean your piece with soapy, warm water to remove any grime and dirt. Then, place your salt paste on the piece and allow it to sit for 30 minutes. Wipe off with a clean, soft cloth or sponge. Be careful not to scratch the surface with the salt cleaning solution. Salt can be abrasive, so you want to be gentle. 

Mix equal parts salt to lemon juice for cleaning hardware easily
Mix equal parts of lemon juice to salt

Baking Soda

Another homemade brass cleaner is baking soda. This natural cleaner is made by mixing equal parts of lemon juice and baking soda. This makes a paste, which you can rub softly across the hardware or solid brass to clean the tarnish. For badly tarnished items, sprinkle baking soda directly on your brass piece and let it sit before wiping it off with a damp cloth.

You will want to clean the surface after with soapy water to remove any remaining residue.

What about Tomato Ketchup?

I have seen this option drift around online but have yet to personally try it. The key ingredient which is at work here is the vinegar in the tomato ketchup. The idea is to place ketchup on the brass object and allow it to sit for 30 minutes to an hour. After this, you clean it with a mild soap and buff it if necessary. I have not attempted this option, as I prefer using products designed for cleaning brass, such as Brasso. It could be worth the try if you are working against the clock and only have ketchup available at home.

Clean Brass Hardware with a soft cloth and a solution of salt and lemon juice

Final Thoughts

Vintage hardware brings so much character to the furniture we refinish that it can be a good idea to strip old paint and remove years of grime and dirt to make those brass knobs sparkle again. It’s a simple process to clean brass hardware. Like all activities we do in the workshop, we need to consider our health and safety. Therefore, stay away from boiling vinegar without taking the proper precautions. It’s simply a bad idea! There are so many other options and simple solutions to cleaning brass that you do not need to put yourself or your family in danger. I would love to know what your favourite method of cleaning hardware is. Let me know in the comments. 


Leave a Comment

Your email address will not be published. Required fields are marked *


Author picture

Hey, I'm Sarah, the owner of Bold Wallflowers.

I'm on a self-taught journey through furniture refinishing and restoration, loving every experiment in my workshop.

Join me as I share my discoveries and gained knowledge with our vibrant community of fellow refinishers!

This post may contain amazon affiliate links. As an Amazon Associate I earn from qualifying purchases, if you decide to make a purchase through the provided links, at no additional cost to you.


Join me on Facebook!

Limited Time Offer!
Subscribe and Receive The Beginners Guide to Painting Furniture
and The Fearless Furniture Refinisher's Guide to Shellac.

Get both guides and weekly tips sent straight to your inbox!
Front page to beginners guide to furniture refinishing
Front page to fearless refinishers guide to wood shellac