My s/o apparently has the greasiest head ever, and leaves huge grease stains on his pillowcase/pillow cover (I use a zipper cover under the case to make sure that it doesn't soak into the down pillow). I've tried throwing in vinegar with the wash, but it doesn't really help that much. Suggestions?
OxiClean is pretty great for this, or you can try pre-soaking the pillowcase in a sinkful of warm water and dish soap (the kind designed to cut through grease!), then a good rinse and launder as usual.