Cleaning the Inside of Air Compressor Tank – Guide & Support

Published Categorized as Air Compressor Maintenance, Air Compressor Tank 11 Comments on Cleaning the Inside of Air Compressor Tank – Guide & Support

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When you use your air compressor, it uses air from the surrounding environment which can be full of water vapor or other particulates. This gets into the air stream, and into the compressor tank which can cause damage to itself or air tools further down the line.

It is therefore very important to clean the inside of your air tank, this page will provide you with all the necessary information and some Amazon products that may help.

Table of Contents

Cleaning the Compressor Tank Steps

As pressure builds up and compresses air into your air compressor tank, water vapor gets compressed too and can cause water build-up, and even rusting of the tank’s walls.

One solution to this is by draining and cleaning the compressor tank by following these steps:

  1. Unplug your compressor and release the compressed air from the system
  2. Open the drain valve underneath the compressor tank
  3. Void the entire tank of the water, sludge, oil, and possible rust
  4. Leave the valve open to allow the tank to dry out properly
  5. Close the drain valve completely and ensure its tightened securely

You should conduct this draining of the compressor tank every day/time you use the machine to protect the tank.

Cleaning Products Available on Amazon

Though it is not directly advised to put anything into the compressor tank to clean it, I’ve come across a few recommendations to use Evapo-Rust if you’re having rust issues inside the tank. Given that it is a water-based non-toxic super safe rust remover it may be of great use to you!

FAQs (Frequently Asked Questions)

How do I get rust out of my air compressor tank?

Oil can help retard rust or use a safe rust remover like Evapo-rust. This is a water-based non-toxic super-safe rust remover used for tools and other devices. You want to ensure that the thing you’re using to remove the rust will not damage the inside walls of the tank.

Can you put oil in an air compressor tank?

You can yes, but it’s not strongly recommended. Yes, the oil can help lubricate the tools attached to the line and retard ongoing rusting but you may not ever get the oil out of the tank. With it being in the air stream, collecting crud along its way – you may end up not being able to spray paint, sandblast or complete any tasks that demand clean air.

How do I maintain my air compressor tank?

To maintain your air compressor tank it is strongly recommended to drain the tank every day, or after every use, and leave the plug out to allow the insides of the tank to dry out.

Reader Comments and Responses

Cleaning the Inside of the Air Compressor Tank


My wife brought home my son-in-law’s air compressor for me to use to work on their car and it got air left in it for a long time without being drained. It has gotten rust inside. is there any way I can clean it or do I need to replace the tank?


John, you don’t say how big an air compressor is, so I wonder if the effort is worth it, if it’s a fairly low-cost DIY home compressor?

I suppose, if you were really handy and could disassemble the unit, you might try a light sandblasting, but then that would strip off whatever protective coating that might be left inside the tank.

You could oil the inside of the tank once disassembled, that might help retard ongoing rusting.

Again, depending on the cost of the unit, I wonder if the effort is worth it?

From now on, of course, make sure you leave the drain valve open when your compressor is stored.

Does anyone else have any thoughts for John?

Clean an old air compressor tank, what's it worth?
Clean an old rusty air compressor tank, what’s it worth?


Air tool oil could coat the tank. it’s good for the tools, too. though, if you’re ever going to use the compressor for spray painting… I don’t know if it’s a good idea.


Interesting thought. I’m against injecting oil into the tank. Even though the air tool oil is good for lubing tools, by the time that oil gets into the air stream, along with all the other crud that’s in the tank bottom, that wouldn’t be good for tools, nope, for sure not.


DO NOT ADD ANY type of rust preventative, or coating of any sort!!! If you add oil into that tank or any type of rust preventative, you will NEVER get it all out, and say goodbye to ever wanting to spray paint, sandblast, or any other air function that needs to be clean..the sulphuric acids and other chemicals in rust converters will ruin air tools one after another.

No matter how many filters etc you have just ruined this tank for future applications..I build pumps, sandblast, and paint from a shop from my home. The factory doesn’t coat the inside of the pumps because of heat transfer… an uncoated inside of the tank will absorb a lot of the heat, which in turn produces a lot less moisture in the tank… if you coat that tank the pump will get 4 times hotter than designed, and the harsh residual chemicals in it will ruin every air tool you use thereafter.



Just a guess here as I have never tried it on a compressor tank, but I use Evapo-Rust to remove rust from my tools. It works quite well, and it is reusable. You would need to fill the tank and leave it overnight then rinse it out and dry it. Evapo-Rust only attacks rust, so it is safe to use. I keep a bucket in the garage that I drop rusty tools into. But it might cost more than the tank is worth.

Another option might be to drop some large ball bearings or nuts and bolts into the tank and shake it. That would break up any flaking rust. Again, I have never tried it.


Thank you for the suggestions, Chuck.

Have some tips for cleaning the inside of air compressor tank or any questions? Please add your comment here, along with photos if applicable, to help others help you with your compressor and equipment problem!

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I am repurposing a Dewalt Capsule air compressor tank (2 gallon) to a Chilled water/glycol reservoir tank for a workstation/Server rack liquid cooling system im working on…. I have a few questions someone might be able to answer… 1.) How do i clean the inside of the tank or remove any light possible rusting?? Do i coat the inside? if so with what? There are 2 fitting bungs on the tank, 1 is 1″npt i believe and the other is a drain with twist ball valve 1/2″ npt i think.. Should i cut a whole at one of the cap… Read more »

Given your questions, I think you’d be better off just buying a tank that suits.
You’re basically building a refrigerator, right? Why not use a small refrigerator/freezer?

My first thought was if you had a large enough container, like a clean garbage can, you could strip the tank of all components and use electrolysis to remove the rust. I have had great results with using this method to remove rust from places out of reach. Look up electrolysis rust removal. I think you would find it to be a good solution to your problem.

Have got an air compressor from a family member and when I drained water from the drain port it was thick sludge. I eventually stripped the compressor down so I was left with the tank open and can see inside, it is thick with a rusty sludge all round.
Can I hose the inside to remove the rust and allow it to dry before re assembling.

Yes, but you want to have that tank hydrostaticly tested before you use it. If a lot of that sludge is rust, the tank bottom may be dangerously thin.

My tank only has 100 liter capacity. I poured 3 liter Evapo-rust into it and left it sitting in the bottom permanently. I know this resuls in 3% reduction of capacity but also provides a continuous protection against rust. Condensation is not a problem because Evapo-rust can be diluted with water. It’s a non-hazardous rust remover which only attacks rust. Safe on everything else including paint, rubber, skin etc. In my opinion all tanks should be hot dipped galvanised and others without coatings banned. There is no reason for leaving the inside uncoated and rusting away which potentially can result… Read more »

PCbeachrat… I work for a major brand air compressor company who shall go unnamed… We offer coated and uncoated tanks. The heat transfer claims he makes are utter hogwash. He is literally Making. Things. Up.

I just wanted to clarify that many manufacturers do coat the inside of their tanks some charge over $200 to do so. That would seem to perhaps void the input of the above poster that untreated metal handles the heat better, not sure why someone would think that?

Maybe PCBEACHRAT (is that Pacific Beach?) will come back and explain – I’m not sure he’s including paint, and the other things would apply for needing really clean air, but ruin the pump? I dunno either.

As an engineer, we spec tanks with coatings all the time. Of course, the coating has to meet specifications so it’s not just any coating. But the claims of the first individual seem to be very inflated or they used a non-compliant coating or did not account for other system effects.

Thanks for that, Ben.