Vegetable oil spilled or splattered onto a concrete surface will absorb into it, if left unattended. Since concrete is hard and durable, most people believe a stain on concrete will merely sit on the surface. But concrete is porous by nature and absorbs oily and wet stains. When the vegetable oil is left on the surface and absorbs into the cement, it causes discoloration and acts like a stain magnet, attracting more dirt and debris.
Pour sawdust over the vegetable oil stain on your concrete surface. Use enough sawdust to cover the stain and create a mound over it. Allow the sawdust to absorb the vegetable oil for 30 minutes.
Sweep up the soiled sawdust with your broom and dustpan. Discard the oily absorbent in the trash can.
Spray water on the site of the vegetable oil stain using your hose. Use enough water to make the concrete wet without creating a puddle.
Cover the wet stain with powdered laundry detergent. Scrub the detergent into the concrete, along with the water, long enough to create soap suds. Allow the soap suds to dry on the concrete; as they dry, the suds will emulsify and draw out the vegetable oil stain.
Remove the dried soap solution by sweeping it up with your broom and dustpan. Rinse off the concrete surface to remove any remaining soap solution. Let the concrete air-dry overnight.