Ok ladies, please don't choke when you gasp at what I'm about to say. Brake cleaner will take grease out of fabric.
I work in a machine repair shop and grease has found it's way onto many different clothes of mine -- all kinds of fabric. Before I wash the item, I spray with brake cleaner and blot and rub till it is out. Then I wash it right away. Having said that, we use it at work on car seats, office chairs, etc., and then don't wash them and they are fine, but that's different fabric than quilts. On a quilt I would use it as a last resort and then wash right away. It stinks so do it outside if at all possible.
I did not say it was conventional, but I know it works.
amh