Believe it or not, lighter fluid will take out black grease. DH brought some in on his feet and tracked all the way across the carpet. Got every bit of it out. Today, I took some black grease that got my my tan pants that came from the car door latch. Put a few drops of lighter fluid on the grease, rubbed it with an old wash cloth, added a drop of dish soap just to be sure and laundered as usual. I've never had the lighter fluid leave a mark but you might try it in a corner just to be sure.

Acetone also will work as long as its an ALL COTTON quilt no man made fiber. Hubby told me about this and it does work but it will melt polyester and rayon. But acetone, dab or blot but the acetone will dissolve the grease. Of course without saying do this is well vented area and no smoking while doing this. Good Luck

Try on a scrap before your quilt

T