Years of neglect have left my mother’s garage looking like a toddler’s bib after an ice cream party. I use kitty litter to clean the excess oil, but for old stains, that's not enough.
Kitty litter is an effective tool for sopping up excess oil. It might not get everything, in which case you can remove the stain with a degreaser, laundry soap, or dish soap.
Preventing Stains is Easier than Cleaning Them
Most older cars drip some fluids here and there.
The best way to deal with the stains is right away before the fluid has time to be absorbed into the floor.
Concrete is porous and over time fluids like oil work their way into the floor and leave it weaker and vulnerable to cracking and chipping.
Protect the Concrete from Future Spills
A cost-effective but not terribly attractive strategy is to lay down cardboard on the floor under the car to catch the drips.
You can also protect your floor by painting or sealing it.
You can use a penetrating sealer to stop oil from absorbing deep into the concrete.
A coating like paint, epoxy, acrylic, or polyurethane, will prevent oil from reaching the concrete. Coating a floor is more difficult than adding a penetrating sealer.
If you're thinking about stopping future spills from causing problems, you might want to see our articles:
- Garage Floor Coatings: Epoxy vs. Paint, Which is Better?
- Protect the Concrete Garage Floor with a Densifying Sealer
The Best Way to Use Kitty Litter
Using kitty litter by itself can work well but only if the stain is fresh and only if you leave it on for a while. There are other products that work better than litter, especially on older stains such as Oil-Dri (Amazon link). Use the same process as for litter.
What you’ll need:
- heavy-duty paper towel or a paint scraper
- cheap clay kitty litter
- stiff scrub brush
- dustpan and broom
- optional cardboard floor covering
If you are using litter, be sure to use the cheap stuff. It is more effective as it doesn’t have perfumes and doesn’t clump.
- First, you want to blot up as much as you can with a heavy-duty paper towel or if it is old and goopy you can scrape it off with a paint scraper.
- Cover the stain with the kitty litter and use the scrub brush to grind it into the stain. If it looks damp add more and repeat the grinding process.
- At this point, you want to leave it alone for a while (like a day or so) and let the litter do its work.
- It will begin to pull the oil and moisture from the cement.
- You can cover up the spot with cardboard if you like.
- Once the litter is wet it had done its job and can't absorb any more.
- Check-in on the litter-covered area.
- If it starts looking moist add more litter and grind it in.
- If it’s really damp clear off the wet litter and repeat the process.
Obviously, you don’t want to use the litter for anything, especially not for your cat.
Kitty Litter or Oil Dri Mixed with a Degreaser
If you have a stain that’s proving difficult or has been on the floor for a while, consider using a degreaser such as Oil Eater in conjunction with the kitty litter.
What you’ll need
- face mask, eye protection, and gloves are recommended
- bucket of water
- Oil Eater or similar degreaser
- stiff nylon brush
- paint scraper
- cheap kitty litter
- dustpan and broom
- garden hose with sprayer nozzle attached to running water
- First, wet the area.
- Then mix a strong solution of degreaser and water and scrub it into the stain.
- Let it sit for about 15 minutes but do not let the solution dry.
- If it starts to dry scrub some more degreaser solution on the area. Use the paint scraper to scrape away any standing water or suds from the stain.
- Pour a liberal amount of the litter and grind it in with your feet or the stiff brush. if the stain is damp add more litter and repeat. There should be a good layer of dry litter or Oil Dri on the surface.
- Let this mixture sit overnight or longer.
- If it gets damp add more litter and grind it in.
- Once it has sat for some time (overnight at least) sweep away the litter and discard it.
- Rinse with the garden hose until clear.
Powder Laundry Detergent or Degreasing Dish Soap
This method uses no kitty litter, only detergents and water, and muscle. What you’ll need:
- putty knife or paint scraper or heavy-duty paper towels
- powdered laundry detergent (I've heard that Nascar pit crews use Tide)
- stiff nylon scrub brush
- garden hose with sprayer nozzle connected to running water
This is a good way to deal with fresh stains. First scrape and/or blot away any standing oil and sticky residue from the area. Mix a very strong solution of detergent and water. Scrub it into the stain with a stiff nylon brush. Let it sit for a while.
DO NOT LET IT DRY.
Letting the mixture sit gives the detergent a chance to emulsify the oil.
Grab your garden hose with a sprayer nozzle and spray the residue away.
The Poultice Method
The idea of a poultice is that you create a paste of a solvent like acetone mixed with a very fine absorbent material like diatomaceous earth and apply it to the stain and allow it to draw out the oil. This method is best for a small stubborn area as it may not be cost-effective for a larger stain. What you’ll need
- absorbent material (diatomaceous earth or fine ground kitty litter)
- a solvent such as acetone
- trowel or putty knife
- plastic sheeting or wrap
- brush and dustpan
In the bucket, mix the absorbent material with acetone. Add enough acetone so that the texture turns to a paste. Use the trowel to smear the paste onto the stain. Cover the area with plastic wrap. Let it sit for a few days.
The solvent penetrates the oil and lifts it out of the concrete where it is absorbed by the absorbent material. Remove the plastic and sweep away the absorbent.
Spray Lubricants for a Scrub-free Method or Oven Cleaner
Use can use a lubricant to loosen a small stain. This method is not cost-effective for a large stain, but it is a low-effort method. What you'll need:
- WD-40 lubricant
- spray hose
Spraying a lubricant like WD-40 on the stain. Wait 15-20 minutes. Hose the area until clear.
Specialty Cleaning and Bioremediation Products
There are a number of specialty products on the market that will clean oil from your concrete floor. Oil Eater and Oil Dri are good choices I already mentioned.
Pour-N-Restore is a good bet for small stains as well. You just pour it on the stain let it absorb and dry then sweep up the residue powder.
There are also products that work by letting microorganisms eat the hydrocarbons in the oil thereby removing the stain. When there is no more oil the little micro-organisms just die off.
This is by far the least toxic and lowest effort method to cleaning oil stains no matter how old they are.
Eximo and Terminator-HSD are two of the most popular of these products. With Terminator-HSD you need to spray a little water on it to activate after you put it on your stain Eximo uses no water and no effort.
Mild acidic solutions such as white vinegar or citrus-based cleaners do well on rust.
Some people use lemons but frankly, I’d rather make lemonade with the lemons and drink it after using the vinegar on the floor.
You may need to do a few passes depending on the severity of the stain. There are some commercial products such as Goof Off as well if you find no success with the vinegar.
One Last Word of Warning
Some people advocate the use of muriatic acid to clean concrete floors.
Muriatic acid is what professionals use to abrade the first layer of concrete before refinishing it.
Acid does not absorb oil nor does it eat away at oil.
It does however eat your concrete.
It is also toxic and dangerous to work with.
Muriatic acid fails on two counts. It doesn’t do what you want and it damages the floor you’re trying to preserve.
Although kitty litter is a low cost go to that has been around for decades it may not be enough to deal with tough stains that have embedded themselves into your garage floor.
It is a good idea to have a bag of the cheap stuff on hand as well as some good paper towels or shop towels in the garage.
After you’ve gotten your floor all nice and clean read about whether to do the next step and protect it from future abuse here: Should I Paint my Garage Floor?