Pour a few drops of dish soap on to a dish cloth and rub the cloth under the kitchen tap. Rub the soapy cloth on the oil stains on the wall soon after they occur. Dry the area with a dry towel.
Dab some rubbing alcohol on a rag and rub the wall where the oil splatters have occurred. The rubbing alcohol will effectively cut the grease content of the oil and help lift it. Unless you saturate the wall with rubbing alcohol, you don't need to blot the wall dry, as the alcohol dries quickly.
Place a few drops of white vinegar on to a rag and scrub the wall where the oil has landed. Rub the wall dry with a dry rag after removing the oil spots.