How can I remove grease spots from a silk dress?

Oh, boy this is a tricky one. Silk is washable so I would probably start with a mild bar soap and see if that removes the stain. Then try vinegar. boiling water. If the dress is ruined with the stains, then it won't hurt to try different methods, but I would hand try everything.

have you tried soaking it out in Bio wash powder?

I would let a proffesional do the work, unless you have washed this dress prior to the stain. Sometimes silk will give up a little color when washed. If you spot clean it, it may show.

Try shaking corn starch on spots & wash as usual. This trick worked for me when I washed lip balm in the washer by mistake.

I think this will help! Best of luck :) https://www.youtube.com/watch?v=vUnzwhYnIn4

Rub baby powder into the spot and leave overnight.The powder absorbs the oil. Magical