Concrete Stain Removal: How to Remove 15 Common Outdoor Stains
Even the most well-maintained concrete slab patios, driveways and garage floors suffer the accidental stain.
If you entertain outdoors or just use your house like the average person does, making a mess on the concrete is a fact of life whether nature, your guests or you are responsible.
Take a deep breath and don’t stress.
We’ve identified the most common household concrete stains and removal methods to try before turning to more drastic measures.
Before You Begin
1. Don’t scrub concrete with a wire brush, as it can scrape it.
2. Be mindful of rinsing oil and other chemical stains into plants and other sensitive areas, as well as storm drains.
3. Spot test whatever you do on a small, hidden area of your concrete to make sure no further damage will be created by any of these methods.
4. Think about wearing protective clothing, eye wear and gloves, depending on which method you choose.
5. Concrete counter tops require extra precautions, so consult your manufacturer prior to using any of these stain removal tips.
6. Be careful using bleach or other chemicals on colored or stained concrete as it can discolor. Concrete is often colored in shades of grey so check to make sure yours isn’t.
7. Pressure washers can quickly remove dirt, debris and some concrete stains, but it is also easy to misuse them and damage your driveway, walkway or patio. If you think a power washer might be your best option, consider hiring a professional with experience pressure washing concrete, or do a bit of research on how to properly use a power washer to remove stains without damaging your concrete.
1. Red Wine
If the spill is caught early, blot or wash it into a drain right away.
Add a few drops of tea tree oil and glycerin (can be purchased at a drugstore) to a few quarts of water in a bucket.
Scrub and let sit on the wine stain for 20-30 minutes.
Don’t let it dry too quickly–apply more if necessary.
Scrub again and rinse.
Increase the amount of tea tree oil and glycerin if the stain isn’t lifted.
Alternatively, after rinsing or blotting the initial spill, apply a 1:1 ratio of water to white vinegar and scrub with a sponge soaked with water and dish soap.
Rinse and blot dry.
Apply glycerin with a damp sponge on any remaining stain and repeat the cycle.
2. Potted Plant Stains
They’re so pretty, but moving potted plants around often leaves behind a stain from water getting trapped beneath the pot.
These can be tough to remove so we offer you options ranging from simple to severe.
Using water and dish soap, scrub the stain and rinse.
If this doesn’t work, sprinkle dry detergent over the wet area and let sit for 10 minutes.
Pour hot water (be careful not to burn yourself) over the detergent and scrub well.
Stain still showing?
Cover it with distilled white vinegar and leave for a few hours without allowing it to dry.
Next, try a 1:2 ratio of oxygenated bleach and water.
Apply and let it soak for 10 minutes.
Scrub using more hot water.
Lastly, if this fails, try trisodium phosphate which can be bought at a hardware store, however, keep kids and pets away from it.
Mix 1 cup of trisodium phosphate with 1 gallon of water and leave on the stain for 20 minutes.
If you can, blot it up versus rinsing, as it will kill plants.
It’s unattractive and causes respiratory issues.
Aside from being a health hazard, it’s also slippery.
Mildew often results from moisture trapped by plants covering areas of concrete.
Make sure to keep plants pruned and away from the concrete.
It’s important to kill the mildew and sometimes the sun and ventilation is enough to do that.
Otherwise, you’ll need a mildewcide.
Here is a recipe for a mildewcide developed by the U.S. Department of Agriculture’s Forest Products Laboratory that can be mixed up at home.
Pour 1 quart of chlorine bleach into 3 quarts of water.
Add 1/3 cup of powdered laundry detergent.
Apply with a brush to mildew stains.
Let it sit until the black or green stains turn white, but don’t let it dry.
4. Moss and Algae
Moss and algae can spread rapidly if not controlled.
Using Simple Green, a scrub brush and a hose can help small areas.
Or, try distilled white vinegar and a scrub brush.
For larger areas, homeowners report success eliminating algae by attaching a liquid fertilizer delivery device to the end of a garden hose and filling it with pool chlorine.
For additional options, read this guide on removing moss from paving stones. Most of the methods will also work to remove stains on concrete.
5. Sidewalk Chalk
Even chalk that’s meant to be used on the sidewalk can be difficult to remove.
Using a brush and water, rise off as much sidewalk chalk as possible.
Next, apply Soft Scrub and work in a circular motion.
If you prefer avoiding commercial cleaners, you can also create a paste by mixing baking soda and water for use a mild abrasive.
You let the dog out first thing in the morning and trip over the door sill– launching coffee all over the concrete patio.
It happens to the best of us.
Coffee is tannic, like wine, so use a 1:4 ration of glycerin to water on a sponge to scrub and remove it.
Washable crayons will probably remove with soap and water.
Non-washable crayons are a different story.
Try using an oil-based lubricant or cleaner like Goo Gone or WD-40.
Use a scrub brush or toothbrush to get the crayon out.
Wipe away the crayon and cleaner.
If there’s an oil-like film remaining, use dish soap and water to remove it.
Patio furniture, garden tools and other metal objects can leave a dreaded rust stain on a concrete patio or driveway.
To eradicate, mix unsweetened Kool-Aid lemonade with hot water.
Scrub and rinse.
Or, pour distilled white vinegar over the stain and let it soak in for a few hours.
Then, scrub the stain with a brush.
Blot occasionally while scrubbing to absorb rust.
9. BBQ Grease
If your juicy steak splattered grease on the concrete patio, make a paste of powdered laundry detergent and water.
Cover the stain with 1/4 inch of paste and securely tape plastic wrap on top.
Leave for 24 hours.
Scrub and rinse.
Repeat, if necessary.
10. Oil And Grease
If it’s a fresh stain, grab paper towels and mop up the excess liquid.
Make sure to dispose of them safely.
From here, you have several options.
Scrub with some dish soap and water using a old towel or nylon scrub brush.
Blot up the excess liquid, as it’s not the best thing in the world to rinse it elsewhere.
Another strategy that seems to work well is using kitty litter to soak up the liquid.
Cover the area with kitty litter and grind it in wearing old shoes.
Consider wearing a mask to avoid inhaling any kitty litter dust.
Sweep up the kitty litter and rinse the area.
If this does not work, you may try spraying a generous amount of WD-40 over the stain.
Blot up and make sure to rinse the liquid off of the area.
If the WF-40 also does not work, you can try spraying a generous amount of oven cleaner on your grease stain.
Let sit 5-10 minutes and use a high-pressure hose to rinse off.
Repeat, if necessary.
11. Berries and Other Dark Fruit
The sun can dry stepped-on berries into an unsightly stain.
In this case, using soap will actually cause the stain to set.
Mix flour and hydrogen peroxide to form a thick paste similar in consistency to peanut butter.
Cover the stain with the paste in a layer that’s about 1/4 inch thick.
Securely tape plastic wrap over the paste and let sit for 24-48 hours.
As the paste dries, it will lift the berry stain from the concrete.
You may need to repeat this a few times to achieve victory.
12. Commercial Salt Stains
This is a stain prevention tip.
If you live in an area where it snows, instead of using commercial salt to melt the snow in your walkways and driveways, use baking soda.
The commercial salt can stain; whereas, baking soda doesn’t.
13. Leaf Stains
As pretty as foliage is, the compounds that give it gorgeous color can actually be absorbed into concrete.
Scrub a mixture of dish soap and water on to the stain and rinse it off using high pressure from a garden hose with a nozzle.
It this doesn’t work, try using OxiClean.
Let it sit on the wet stain for about 10 minutes or so, then scrub in a circular motion.
14. Pet Urine
Fortunately, most pet stores carry safe, enzymatic urine removal products and if you have a pet, it’s wise to keep some on hand to tackle urine stains and odor.
First, scrub the concrete stain with dish soap and water in order to remove as much urine as possible.
If you catch the stain early, this might be all you need in addition to some sunshine.
Odor can be further reduced by an application of distilled white vinegar; however, the pet store products are most effective.
Did you know that you can identify pet urine on concrete with a black light?
- Take a look at Urea Z: The Pet Odor / Urine Smell Remover
15. Cigarette Stains
The person who tossed that cigarette butt on your concrete had better have brought washing soda as a hostess gift.
You can buy washing soda (it’s different than baking soda) at almost any store that sells cleaning supplies or turn your baking soda into washing soda by sprinkling some onto a half-sheet pan (or similar) and bake it at 400 degrees until it loses luster and becomes grainy.
Of course, just buying washing soda is easier, but it does require a trip to the store.
Use a mixture of washing soda and water along with a brush to scrub the stain out.
Your best bet is to diligently spray down and seal outdoor concrete regularly, because it is so porous.
The other reason why keeping liquid from absorbing into concrete is important is because it puts stress on the concrete, leading to cracking.
If the above stain removal measures don’t work, contact a professional.
And, don’t panic–concrete stains are a part of life so no one expects it to look flawless forever.
Do you have a common stain and solution that we missed?
Share it with us below…