stains on cement driveway

[Margie Davis]

I've been in my new-construction house for six months and want to get rid of the stains on the driveway. It looks like there are three different types of stains: rust, oil, and bird poop. Any ideas about what to use?

Thanks

[Roger]

Rust: muriatic acid (= hcl) , or Naval Jelly (phosphoric acid) spray - others may select the best from these two possibilities.. Use stainless steel brush., then rinse. Oil: Cat Litter. Pour on spot liberally, grind in with your heel to turn to powder, and let sit there a few days, about 1/4 to 1/2 inch thick layer. Poop: Easy. Try putty knife, then high pressure hose or good small-stream nozzle on garden hose.

[jim]

wife gets a can of oven cleaner from the food store.. it will eat grease and get rid of most stains.... thats why you have to be careful with it when spraying it in an oven... get the good stuff.. we tried the trash they sell in the dollar stores,, but i guess thats why its in the dollar store, the stuff they sell does not work......

[Gary]

Oil - cat litter, carburetor cleaner, or brake cleaner (cleaners available at auto supply)

[RB]

Be cautious trying to remove rust with muriatic acid or hydrochloric acid (chemically the same thing.) In all likelihood all you will do is etch the concrete and still have rust stains. There are numerous cleaners intended to remove rust which are based on oxalic acid. Many are intended for use as bathroom cleaners, just look at the ingredients or go to a good paint store and buy a small container of wood bleach (oxalic acid). Dissolve the oxalic acid in water, it's highly soluble so don't start with too much water and use that. Oxalic acid reacts with the rust and creates iron oxalates which unlike rust are soluble in water.

Oil is best addressed with absorbents like clay as in kitty litter, and then solvents. A good auto supply store should have oil removers for concrete. No profound thought on the bird issue.

RB

Margie Davis wrote:

[Margie Davis]

Thanks for your fine suggestions.

[PJx]

I use gasoline scrubbed in with an old broom, followed up by 'Tide' detergent sprinkled on the damp concrete. Then dump a bucket of hot water on it. Presto. Stain gone.