How to clean dirty oil / grease stain on polyester

Gently remove grease residues with a rounded knife blade. Then put a small amount of butter or margarine on the stain, and leave for 5 minutes. Remove excess with the back of a knife.

Place the garment on a clean white cloth and dab the stain with another white cloth soaked in pure white spirit. Proceed with a normal wash, according to care instructions.