Remove oil stains from concrete driveway using baking soda and hot water, or trisodium phosphate and hot water. However, trisodium phosphate is not applicable for asphalt driveways. For stubborn oil stains, apply muriatic acid over the stains, allow the acid to sit on the stains for a few minutes and rinse the driveway with water. Be sure to protect hands and eyes with gloves and goggles respectively when using the acid.
To use baking soda and hot water, start by pouring a little water over the stains to make them damp before spreading the baking soda over them. Leave the powder to loosen the stains for a few minutes before pouring hot water on them. Allow the water to cool, and use a scrubbing brush to scrub off the stains from the concrete. Rinsing the powder residue from the concrete with water and repeating the process as needed to remove any stain remnants completes the process.
To use trisodium phosphate and hot water, first dampen the stains with cold water, measure 1 gallon of hot water and pour it into a bucket. Add 1 cup of trisodium phosphate, and mix to form a uniform solution. Pour the solution over the wet stains, and allow the solution to sit on the stains for a few minutes to break them loose. Once loose, scrub them off with a scrubbing brush before rinsing the concrete with cold water. Repeat the process until the driveway is free of stains.