Removal of crayon markings from documents

Someone has called me asking about the removal of crayon from a book
she has purchased. I searched CoOL and found a question but no
solutions. If anybody has any solutions or advice I would appreciate
it.

    **** Moderator's comments:   This is another opportunity to
    remind you all that responses to queries should normally be sent
    to the list so that we can all benefit from the answers. If you
    receive responses to your query which were not also sent to the
    list, please do us all a favour and post a summary.

Christopher McAfee
Rare Book Conservator
Brigham Young University

                                  ***
                  Conservation DistList Instance 9:61
                  Distributed: Thursday, March 7, 1996
                        Message Id: cdl-9-61-017
                                  ***