Removing stains from concrete – rust or tar

Removing stains from concrete – rust or tar

Have you noticed unsightly stains on your concrete driveway, walkway, or patio? Perhaps your once pristine BBQ spot has acquired stubborn stains from years of use.

Don’t let these blemishes detract from the beauty of your home’s exterior. With little help, you can restore the natural luster of your outdoor surfaces and make them look as good as new.

After 10 or 20 years of being on the ground, concrete is bound to end up stained. Whether it’s weathered, stained, or even if there is rust or tar on your concrete, there are some steadfast ways to cure all of these problems and get your concrete looking new again.

Without replacing the entire slab, I will show how to remove those stains from the concrete.

Rust stains might happen when something rusts is left on the concrete for a long enough time. It is sometimes more apparent, as it might not show immediately.

It might be car rims, chains, bike stands, or something else that we expect to wait to rust as it still looks good on the outside.

Other than rust, tar might be left behind by an asphalt job nearby or other things like roofing tar. Tar removal is the most difficult when it comes to removing stains in concrete.

Still, even this isn’t impossible when you are armed with information and the right tools for the job.

Removing Tar Stains from Concrete

Tar removal requires an agent to release the sticky tar from the concrete. Some people advise that gas will remove tar from concrete, but gas also tends to leave behind a stain, so you will work double duty if you use gas to clean up the mess.

You will first have to get the tar off the concrete, and then you’ll have to try to get the gas stain off, too. This is a bit counterproductive, so we can try another way.

WD-40 is the best thing I have found regarding tar removal. Not only will this remove tar from your car, but it will also remove it from concrete and skin.

Although we shouldn’t be elbow-deep bathing in WD-40 to get some tar off, it can be used on small areas such as your hands if you get some tar on them while doing a minor roof repair or something similar.

To get the tar off of the concrete, begin by spraying the tar with WD-40 to soak the entire area. Allow this to set on the concrete for about 5 minutes so that it has time to break the tar up a bit.

Using a wire brush (or scrub brush), scrub the tar and use a hose to rinse the area. If this doesn’t break the tar up and clean the concrete, apply some more WD-40 and allow it to sit again for at least 5 minutes. Scrub with water and a wire brush once again.

Once you have removed most of the tar, you can usually use a pressure washer to clean the remaining tar off the concrete. The WD-40 won’t stain the concrete either, so you won’t be doing double duty trying to clean up two messes.

A small amount of dish soap and water can also break up any remaining debris and tar that may have been left behind. Scrub some soapy water around the concrete area with the tar on it, and then use a hose with a high-pressure sprayer or preferably a pressure washer to remove the remaining stain from the concrete.

Tar removal is just a gradual process of breaking it up until the entire stain has been removed from the concrete.

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How to Get Rust Stains Off Concrete

To remove a rust stain, you have to use an acid-based liquid on the concrete surface to pull the stain out. Lemon juice and salt/baking soda or white vinegar will do the trick.

How to use lemon for rust removal

For the lemon juice and salt method, spread some salt on the rust stain. After that simply pour a lot of lemon juice all over the rusty salt spots and leave it there until it soaks in. Depending on the intensity of the stain it could be minutes or hours.

Another way is to make a paste with baking soda and lemon and spread it on the rust spots. Let it sit for the same amount of time as the salt and lemon method. Depending on the stain, it needs to be tested out how effective it is.

Next scrub at the rust stain with either a scrub brush or a large swishy broom with rough bristles. Scrub in a circle to help break up the rust stain, adding a cup of water so you can kinda froth the stain up. It will look (and smell) a lot like drying blood. It should mean that you’re getting somewhere.

Let the frothy, bloody-smelling mess sit for another 10 minutes or so, allowing the lemon juice to take effect. Then rinse the concrete off with a hose.

If you have a power washer, then you can almost forget about cleaning the stain and just blast the rust out of the concrete. Otherwise, you’ll have to put your thumb over the water stream to create pressure and blast the rust stain away.

How to use vinegar rust removal

Vinegar is more effective, but it has a strong odor. It’s also good for old tools, rusty nails, and pretty much anything else that is rusty. It could take somewhere from 30 minutes to an hour, depending on the stain again.

Like with lemon juice, you can use salt with it. Add the salt in the white vinegar, 1 cup of salt to 1 gallon of vinegar should do the trick. It will make the potency of the acid higher so it should be more effective.

If the stain is still slightly there then pour more white vinegar salt mix on the rust stain. Then repeat the same process again to get rid of the stain. Wear gloves when pouring vinegar or lemon juice, as the acidic liquid can really burn your cuts.

After you’re done with scrubbing the rust stain, wash the concrete well with water and hopefully the smell will disappear soon.


Rust and tar might be the most common stains on our driveways. The main cause is our vehicles. The good thing is, those stains can be taken care of quite easily if you know what you’re doing.

If we take care of these problems as fast as possible, they won’t cause much aesthetic harm. Left unattended for too long, these can take some time to clean.