Removing an Unknown Stain from a Wool Coat?

I have a red wool coat with a stain on the left cuff right at the fold. It was dry cleaned, but some of the stain remains. The stain is of unknown origin. Any suggestion on how to get rid of it? It looks as though it was oil. If all else fails, I plan to embroider over it or add some sort of decorative tape to cover it.

By Liz from Salisbury, NC