How to Remove Stains, Rust, and Rainbowing from Stainless Steel Mugs and Bottles

​(10 minute read)

How to Clean Stainless Steel Mugs and Bottles

So, what exactly are the best ways to remove stains and rust from your stainless steel bottle?  And what exactly is that oily-looking rainbow color that you sometimes see, and is it harmful?

It honestly gets really confusing, and everyone seems to have their own trick or solution.  So today, let's talk about and test eight of the most commonly-mentioned options to see which are the best for removing stains, rust, and rainbowing in stainless steel water bottles.

You'll see some that work amazing, and others that don't so much at all.  So let's get started and learn how to make your stainless steel bottle look like new.

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Best for Stains and Rainbowing (Not Rust)

Given that this is the most common question, we wanted to highlight this answer first by showing the cheapest, fastest, and easiest ways to remove stains and rainbowing from stainless steel mugs and bottles.

Keep reading below to learn more about our tests, as well as which are the best cleaning options for removing rust.

Cheapest

(harder to use in narrow bottles)

Step 1:
Pour some baking soda on the stain.

Step 2:
Add hot water and mix it into a paste.

Step 3:
Spread the paste around on on the stain and let it sit for ~10 minutes.

Step 4:
Scrub it around, wipe it off, and rinse.

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Fastest

(harder to use in narrow bottles)

Step 1:
(for their Soft Cleaner formula)
Read the instructions on the bottle first, because you need to be a little more careful compared to just using baking soda.

Step 2: 
Pour some Bar Keepers Friend onto the stain.

Step 3:
Immediately start scrubbing and wiping it around with a paper towel or rag.

Step 4:
After 30 seconds, wipe it off and rinse.  Don't let it sit for more than 60 seconds.

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Easiest

(easy for any mouth diameter)

Step 1:
Fill up your bottle with hot water (ideally close to boiling)

Step 2: 
Add one Bottle Bright tablet, and let it sit for 30 minutes.  Note that the bubbles may cause the water and foam to spill over some at first if you filled your bottle to the rim.

Step 3:
After 30 minutes, use a long-neck brush like this one to scrub around inside the bottle, then rinse.

See on Amazon

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​Video: How to Remove Stains, Rust, and Rainbowing from Stainless Steel Mugs and Bottles

​​​​​​​​​​​​We also cover this info in a YouTube video if you'd prefer to watch the recap that way.

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Amazon Associates Disclosure
​BottlePro is part of the Amazon Associates Program.  There are a few products linked later in this article, and if you make a purchase using one, we earn a small commission at no cost to you.  Big thanks if you use one because it really does help!

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Stains vs Rust vs Rainbowing

​First, it helps to know the difference between stains, rust, and rainbowing because knowing what you have can change which type of cleaning agent or method you should use.

Stains

Coffee and Tea Stains (in 16oz Hydro Flask)

Stains are most commonly formed if you are a regular coffee or tea drinker.  This is because of tannins, which most people associate with wine, but they also exist in coffee and tea.  They're basically organic compounds you find in things like fruit, bark, and leaves, and fun fact, the name "tannin" comes from how people can use tree bark to tan animal hides when making leather.

​Because tannins are so small, they work their way into the microscopic pores and imperfections in stainless steel, which creates that staining effect.

​Another type is water stains, which is when water droplets dry up and leave behind oils or dissolved minerals like calcium, and it's a lot more common if you live in an area with hard water.

​But notably, none of these stains actually damage your bottle.

​Rust

Rusting

Rust on the other hand is corrosive and can leave lasting damage if left unchecked.

Regular carbon steel corrodes because the iron in the steel reacts with water and moisture in air to form iron oxide, also known as rust.  Stainless steel is different because it contains a percentage of chromium, along with a few other metals.  The amount of each type of metal varies based on the type of stainless steel you have, but the important detail is that the chromium in stainless steel forms a protective chromium oxide layer, also known as a passive layer.

​That's what actually prevents rust from forming, and it's why stainless steel stains less.  But it's really thin, typically just a few nanometers thick.

​Rainbowing

Rainbowing in a Corkcicle Mug

Rainbowing is what happens when that chromium oxide passive layer gets a little thicker.  When stainless steel is heated up, that can actually increase the thickness of that oxidized top layer, creating that rainbowing effect.

​Because it's related to heat, that's also why you sometimes hear rainbowing referred to as heat tinting.  Even though it looks a little weird and oily, rainbowing stainless steel bottles are totally safe to use.

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What We're Testing

Sometimes it's hard to tell exactly what's a stain, rust, or rainbowing, especially if it's really bad because maybe there's a combination of these issues.  And even though stains and rainbowing aren't inherently unsafe, they make it more difficult to know if a bottle is truly clean.

For those reasons, it can be a good idea to clean bottles regularly so they look like brand new stainless steel.  These are eight of the most commonly-mentioned methods you'll find online.

• Baking soda
• Vinegar
• Salt and lemon juice
• Bar Keeper's Friend
• Cleaning tablets (like Bottle Bright)
• Bleach
• Abrasive cleaners (like steel wool and Magic Erasers)
• Cleaning beads

​We're going to test some of these three mugs: a rainbowing Corkcicle mug, a coffee and tea-stained Contigo mug, and a stained and rainbowing Hydro Flask 16oz bottle.

​And I don't have any bottles with enough rust to run multiple tests, but I did accidentally left this camping stovetop outside too long, so that'll give us plenty of surface area to test a few different ways to remove rust.

Corkcicle (Rainbowing)

Corkcicle Mug (Rainbowing)

Contigo (Staining)

Contigo Mug (Staining)

Hydro Flask (Staining and Rainbowing)

Hydro Flask (Staining and Rainbowing)

Camping Stove (Rusting)

Camping Stove (Rusting)

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Test 1 Setup: Corkcicle (Removing Rainbowing)

First on the testing block is the Corkcicle with the heavy rainbowing.

Rather than testing one method after another, I taped off four sections inside the mug so we can hopefully see the differences side-by-side against the exact same types of stain.

Taping Off 4 Sections

Test 1 (Rainbowing): Baking Soda

Sprinkled a bunch on, added warm water to make a paste, let it sit for 10 minutes, then did some light scrubbing and washed it off.

Baking Soda

Test 1 (Rainbowing): Vinegar

Made a 1:1 solution of 5% distilled white vinegar with warm water and let that also sit for 10 minutes.​

Vinegar

Test 1 (Rainbowing): Lemon Juice and Salt

Made a solution then poured that on, also leaving it for 10 minutes.

Lemon Juice and Salt

Test 1 (Rainbowing): Bar Keeper's Friend

Bar Keeper's Friend recommends using it for no more than 1 minute, so I did more of a wipe-on-wipe-off approach over about 30 seconds.

Bar Keepers Friend

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Test 1 Results: Corkcicle (Removing Rainbowing)

Baking soda and Bar Keeper's Friend had by far the best results of these four methods when it comes to removing rainbowing.  The baking soda results did not look at good as BKF, but that's probably because I did not make as even of coverage with the baking soda paste.  It looked really good in the middle where I know there was good coverage with the paste.

Both the vinegar/water solution and the lemon juice/salt solution did not appear to remove rainbowing much at all.

Baking Soda and Vinegar Results

Bar Keepers Friend and Lemon Juice and Salt Results

Test 1 (Rainbowing): Bottle Bright

​Next was Bottle Bright, and for this, I filled the same mug up about halfway with warm water, added a tablet, and let it sit for 10 minutes. (show footage).  You can can how it cleaned some of the mug, but it wasn't as good as I thought it would be.

Bottle Bright Results (Half Full, Warm Water, 10min)

I've used these tablets before with amazing results, so I ran the test again like how I normally use them by adding boiling water, letting it sit for 30 minutes, then scrubbing it some with a long brush.  You can see that really did the trick, and now the whole inside of the Corkcicle looks like new.

Bottle Bright Results (Full, Hot Water, 30min)

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Test 2 Setup and Results: Contigo (Removing Stains)

After that, I tested the Contigo with heavy coffee and tea stains the exact same way using a mug that's been taped into 4 sections.

Again, baking soda and Bar Keepers Friend were great at removing stains, while vinegar and lemon and salt may have removed some of the stains but not nearly as much.

And Bottle Bright worked the same too.  You can see where I filled it halfway up with warm water and let it sit for 10 minutes, but you can really see the difference when used with boiling water and a 30-minute sit time.

Test 2 (Staining): Baking Soda (top middle)

Sprinkled a bunch on, added warm water to make a paste, let it sit for 10 minutes, then did some light scrubbing and washed it off.

Baking Soda Results

Test 2 (Staining): Vinegar (top middle)

Made a 1:1 solution of 5% distilled white vinegar with warm water and let that also sit for 10 minutes.​

Vinegar Results

Test 2 (Staining): Lemon Juice and Salt (top middle)

Made a solution then poured that on, also leaving it for 10 minutes.

Lemon Juice and Salt Results

Test 2 (Staining): Bar Keeper's Friend (top middle)

Bar Keeper's Friend recommends using it for no more than 1 minute, so I did more of a wipe-on-wipe-off approach over about 30 seconds.

Bar Keepers Friend Results

Test 2 (Staining): Bottle Bright (line halfway up)

Mixed 1 tablet with warm water, then soaked for 10 minutes.

Bottle Bright Results (Half Full, Warm Water, 10min)

Test 2 (Staining): Bottle Bright (filled to top)

Mixed 1 tablet with hot water, then soaked for 30 minutes and lightly scrubbed with a soft bristle brush.

Bottle Bright Results (Filled to Top, Hot Water, 30min)

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Test 3 Setup and Results: Hydro Flask 16oz (Removing Stains and Rainbowing)

For good measure, I also cleaned a 16 ounce Hydro Flask bottle.  However, since I'm not able to get my hand inside it, I just used Bottle Bright with hot water, soaked for 30 minutes, then scrubbed it lightly with a brush.  The results speak for themselves!

Bottle Bright Results

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Test 4 Setup and Results: Camping Stove (Rust)

​Next was the rust test using that camping stove.  I used all of the same methods and durations again, each time just testing one side of this flat part of the stove.

Rusted Camping Stove

For rust, lemon juice and salt did much better and seemed to have the best result.  Bar Keeper's Friend and baking soda both removed some rust, but not as much.  And again, vinegar didn't seem to do much at all, and neither did Bottl Bright this time.  Then I added a Bottle Bright tablet with warm water and let it sit for 10 minutes on the vinegar section because that was the side that still had the most rust.  It didn't do much at all, so I reran the test with boiling water and letting it sit for 30 minutes.  But again, Bottle Bright didn't do much.

Test 4 (Rusting): Baking Soda

Sprinkled a bunch on, added warm water to make a paste, let it sit for 10 minutes, then did some light scrubbing and washed it off.

Baking Soda Before/After

Test 4 (Rusting): Vinegar

​Made a 1:1 solution of 5% distilled white vinegar with warm water and let that also sit for 10 minutes.​

Vinegar Before/After

Test 4 (Rusting): ​Lemon Juice and Salt

Made a solution then poured that on, also leaving it for 10 minutes.

Lemon Juice and Salt Before/After

Test 4 (Rusting): ​Bar Keepers Friend

Bar Keeper's Friend recommends using it for no more than 1 minute, so I did more of a wipe-on-wipe-off approach over about 30 seconds.

Bar Keepers Friend Before/After

Test 4 (Rusting): ​Bottle Bright

I added a Bottle Bright tablet with hot water and let it sit for 30 minutes on the vinegar section because that was the side that still had the most rust.  It didn't seem to do much.

Bottle Bright Before/After

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Conclusion

Here were the best results based on visually comparing the different methods.

If you have a stained or rainbowing bottle with a wide mouth that you can get your hand into like a mug or a Stanley tumbler, you may want to try baking soda or Bar Keeper's Friend for stains first because they work really well and are the fastest.  If you can't fit your hand into the bottle, use Bottle Bright with boiling water for 30 minutes, then use a long brush to scrub it and I can almost guarantee that will work.

For rust, try lemon juice and salt first, followed by Bar Keepers Friend.  If your bottle is rusting on the inside and you can't get your hand in there, you can try using lemon juice and salt with a long brush, but it might be difficult to get as much scrubbing force with a brush as much as you really need so you may want to consider replacing your bottle.

For Stains

Best Options:

• Baking Soda (cheapest)
• Bar Keepers Friend (fastest)
• Bottle Bright (easiest)

Not as Effective:

• Lemon Juice and Salt​
• Vinegar

For Rainbowing

Best Options:

• Baking Soda (cheapest)
• Bar Keepers Friend (fastest)
• Bottle Bright (easiest)

Not as Effective:

• Lemon Juice and Salt
• Vinegar

For Rust

Best Options:

• Lemon Juice and Salt
  
• Bar Keepers Friend

Not as Effective:

• Baking Soda
• Bottle Bright
  
• Vinegar

Looking to Buy Some Supplies?

Here are some good options for each of the supplies and cleaning methods mentioned.  Big thanks if you use one of the links to buy...it really does help!

Click on any of the images to see the Amazon listing.

Baking Soda

Lemon Juice

Bar Keepers Friend

Salt

Bottle Bright

Retainer Tablets

Mosolan 3-Brush Kit

I've used this kit for years.  It's not that expensive, and it has a good range of brushes that help with just about any bottle (including a small detailing brush that helps with threads and hard-to-reach spots with many brands).

It's the one accessory we typically recommend everyone has for ANY bottle because it's so helpful.  There are plenty of other brands on the market though, so feel free to shop around.

See on Amazon

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What about Bleach, Abrasives, and Cleaning Beads?

Eagle-eyed readers may have noticed I didn't test bleach, abrasives (like steel wool), or cleaning beads.

Can You Use Bleach to Clean Stainless Steel?

Why You Shouldn't Use Bleach on Stainless Steel

There's a reason why I didn't test bleach.  Yes, it will kill any bacteria and remove some stains, but the problem is that bleach is so corrosive that it can damage or remove the chromium oxide layer, which then makes your stainless steel bottle more likely to corrode in the future by rusting.

You'll see a lot of people say they've used bleach for years on stainless steel with no problems, and I'm sure that's true.  If you use a really mild solution and wash it out quickly, then it's probably OK.

​But in my opinion, I'm not sure why you'd want to risk that with a stainless steel bottle when there are other effective stain and rust-removal options like we've just seen that are less likely to cause damage.

Can You Use Steel Wool or Magic Erasers to Clean Stainless Steel?

Why You Shouldn't Use Steel Wool on Stainless Steel

It also may not be a good idea to use abrasive things like steel wool.  These can scuff up the surface of the stainless steel, adding more of those microscropic imperfections that make it more likely to stain or corrode again in the future.  It's safer to use something non-abrasive like a brush or sponge with the right cleaning agent.

Magic Erasers are made of melamine (type of plastic) and are essentially a much finer abrasive.  For that reason, we typically still recommend using non-abrasive cleaning methods first, like Bottle Bright with a soft bristle brush.  But if that doesn't work, then Magic Erasers could be worth a try.  Because the melamine is softer than steel and it's much finer, Magic Erasers are much safer to use on stainless steel when you need some extra abrasive force.  However, be careful when using them around painted and powder coated surfaces because it's possibly they could lead to cosmetic damage. 

Do Cleaning Beads Work on Stainless Steel?

Do Cleaning Beads Work?

I've seen these mentioned quite a few times, and they're basically just small stainless steel balls.  They're designed so you can drop them through a narrow neck then shake them around, and the impact from the beads helps remove some of the stains.  I'm not 100% sure, but maybe they just jar some of those tannins loose, and apparently they can work OK and I can see how this would be helpful with something like a rounded wine decanter with a really narrow neck.

But they may not be the best solution for stainless steel bottles.  Even though the beads are small, it's probably hard to get them to clean all the corners effectively, like along the bottom rim of  your bottle.

Also, it sounds like you're meant to use them along with some kind of cleaning solution anyways, so why not just use Bottle Bright and a cleaning brush?

​If you have an extremely narrow neck bottle like a classic S'well, then maybe these cleaning beads could help.  But other than that, I'm not sure they're any better than just using a brush, which you should have for your weekly cleaning anyways.

​If any of you guys have used cleaning beads, I'd be really curious to hear what you think in the comments.

Cleaning Guide

And Remember...

Regardless of which bottle you get, always clean it regularly.  Here's our latest guide on the best practices and cleaning schedules for stainless steel bottles so you can keep your bottle in great (and safe) condition.

See Our Cleaning Guide