Niagara Block Inc.
A FamilyTradition Of Excellence Since 1931

There's More
Than One Way
to Remove
Oil From Cement.

Q. I hope you have a formula for removing car "drippings" from a cement driveway. I would appreciate your printing it in your column - V.L.

A. We have had numerous requests for cleaning methods that can remove both grease and oil drippings, as well as rust stains from concrete. We are happy to repeat a couple of formulas that have been published recently.

For grease and oil stains on concrete, we recommend that you first scrub the stains with paint thinner or grease solvent. Then mix one part sodium citrate to six parts water and six parts of commercial glycerin. Add sufficient whiting powder to form a thick paste. A coat of this paste should be kept on the stain for one week and a new paste added when it dries out. Then flush out dried second layer away and the stain should be gone.

For rust stains on concrete, use the same mixture, but if the stain still remains, make another paste of one part sodium citrate crystals to six parts water and add sufficient powdered whiting. Heavy layers of this, spread and dried on the rust stain, will usually remove it.

After cleaning the area treated may look lighter than the surrounding concrete. This solution has a tendency to bleach the concrete. It is a good idea to seal the concrete once it has been cleaned and is free of stains. Use a good masonry sealer available from masonry supply stores or use Thompson's Water Seal.

Another method of cleaning concrete, supplied from one of our readers, recommends the use of trisodium phosphate (an excellent cleaning agent).

First, pour boiling water over the area to be treated. Leave just enough moisture on the surface to absorb the trisodium phosphate when sprinkled generously on the surface.

Use a stiff bristled broom to scrub the mixture vigorously. Let this dry on the surface, then hose down the area treated, again leaving just enough moisture to absorb dry Portland cement when sprinkled over the the dampened area. Use as push broom to again scrub the area with this mixture, then allow to stand two to three hours.

In this formula, the trisodium phosphate helps to remove the oil and grease stains, and the Portland Cement penetrates the pores in the concrete, leaving the appearance of a freshly laid driveway.

Q. One of my tenants spilled and oil-based redwood-color paint on the walkway in front of her apartment. Nothing we have tried seems to touch it. The cement is porous so the color has soaked in.

A. As you have already noted, concrete is porous and paint that has penetrated the surface may be impossible to remove.

Try the cleaning methods listed in the previous question. If those do not work, you might consider painting the walkways or applying a top coat of concrete over the present surface.

Topping is applied with concrete patching material and concrete glue. Consult your masonry dealer for recommendations on topping procedures as well as recommended paints for concrete surfaces.