Whenever I get an oily stain from food splattering while it's cooking, I use...
...a dab of Dawn.
No, not Dawn/MO, or even Dawn/NYS, but Dawn liquid dish detergent.
I use my finger to rub it in and then throw the item back in the laundry pile to wait for laundry day. Launder as usual, and out comes the spot.
This even works on spots that have been "set" by having gone through the laundry once, including the dryer. Works on all colors, even darks.
Michael