How to remove salad oil or cooking oil from polyester?

Spot that asap with your favorite laundry product. never machine dry un you're sure the grease is out.

Test for color fastness and if ok, put Dawn dishwashing liquid on the oil spots (undiluted). Let sit over night. (Cover with a piece of plastic wrap to keep moist). Launder as usual. Stubborn spots may require another treatment. Until stain is removed, do not dry in automatic dryer as this will set the stain.

http://www.howtocleanstuff.net/how-to-clean-oil-stains-from-polyester/

I spray with shout gel spray leave it over night hand wash spray again and machine wash I always have good results.

Cover the area generously with baking soda powder ensuring the stained area is completely covered. Leave on overnight. Vacuum or brush baking soda off; baking soda will have absorbed the oil. Repeat if necessary for larger stains. Launder if needed. Works great on clothing.

Dawn and hot water.