I recently read a newspaper paper column (Vancouver, B.C. Sun) by a lady who had an unfortunate accident in which she fell and broke a bottle of olive oil she was carrying, which soaked her well-loved suit - she had just been to a funeral.  She didn't know what to do about this, but a friend gave her a suggestion - put it in a bag, add a generous amount of plain white wheat flour, shake and leave for a day or two.  Then take it outside and shake out the flour, which by now has absorbed the oil.  She reports that it worked perfectly.  I don't know whether or not this might work with your specimen, but I can't imagine it would hurt it.

Cheers, Giles