Power steering fluid isn't the same thing as motor oil; like brake fluid, it's a hydraulic fluid, and while it usually provides some measure of lubrication to moving parts in your car's steering mechanism, it isn't as thick as oil. It's a petroleum product, though, and as far as your driveway or garage floor is concerned, it produces the same kinds of stains.
Power steering fluid stains, like oil stains, are easier to remove when they're fresh, but if your car has a leak, you probably won't get to the stain right away. If not, prepare for some scrubbing.
Start by Soaking up the Fresh Fluid
Even if a stain looks like it has soaked into the concrete, you can usually remove some of the fluid by covering the affected area with an absorbent material. Use an inexpensive brand of kitty litter with clay pellets -- the clay is super-absorbent and can actually draw fluids out of the porous concrete.
Swish the kitty litter around the affected area with a broom, then let it stay there overnight before sweeping it away. You'll know it worked if the kitty litter has clumped.
Roll Up Your Sleeves
Kitty litter won't have much effect if the stain has dried, and even after soaking up all the fluid that you can, you'll probably still notice discoloration. It's time to get down and dirty with one of the following cleaning products:
Laundry detergent. Pour liquid laundry detergent full strength onto the stain or cover the affected area with powdered detergent and add a few drops of water to make a paste. Leave it overnight, then add a bit more water and scrub with a hard-bristle brush. Rinse well when you're done.
Tri-sodium phosphate. TSP is a strong detergent -- stronger than laundry detergent-- and it's mildly corrosive, so wear gloves and goggles when using it. Spread some on the driveway with a little water or mix a 1-to-1 solution with water and pour it on the stain. Leave it overnight, then scrub with a little water and rinse.
Commercial driveway degreaser. Commercial driveway cleaners are made to remove stains. Follow the instructions on the container when using a specific product, which will probably include scrubbing.
Muriatic acid. Muriatic acid is the Hulk of driveway cleaners, and like the comic book character, it can cause collateral damage if you incorrectly. Always wear goggles and gloves when handling it. Add 1 cup of the acid to a gallon of water. The best way to apply it is to brush it on the stain with an old paintbrush -- never pour it, and avoid splatters when brushing it. Let it work for a short time, then neutralize the acid by spreading lime on the stain, leaving it for a few hours and brushing it into a container for disposal.
It's an urban myth that highway patrol personnel carry a can of Coca Cola in their vehicles for cleaning blood stains from roadways. Whether or not that's true, there's no guarantee it will also work on power steering fluid, but you don't lose anything by trying. Pour some on the stain and, to prevent evaporation, cover the area with plastic. When you remove the plastic, you may notice an improvement after scrubbing. If the discoloration is still noticeable, try again.