Removing marker stains from oil based paint

I am a conservator in private practice.  I recently received for
treatment an oil on masonite painting done by Everett Spruce circa
late 1950's.  The original painting had been covered over by the
artist at some point in a very sketchy manner using a white-ochre
and red acrylic paint. The top sketch included heavy black outlines
of figures and objects which were done using a permanent black
marker pen.  At the owners request I have removed the acrylic
overpaint and uncovered the original, intact, underneath.  However,
the black marking pen appears to have penetrated deeply into the oil
based paint layer and detracts from the original image.

I have tried to 'draw' the stains out with several different
solvents with little or no effect.  I have exposed these areas to
sunlamp, thinking that the marks might be light sensitive.  Also, no
effect.

I would appreciate any personal experience and/or treatment advice
as to how one might remove these stains.

Dennis Baltuskonis
Art Conservation Services
San Antonio TX 78213


                                  ***
                  Conservation DistList Instance 16:7
                   Distributed: Friday, July 19, 2002
                        Message Id: cdl-16-7-011
                                  ***