Removing paint from plaster moldings

I am working on an eighteenth century house with Adamesque
neoclassical ceilings: intricate, shallow-cast and run-in-place
plaster moldings.  The cast pieces are gypsum and the run-in-place
parts are lime. The surfaces have been repainted some 15-20 times
resulting in a loss of the depth and delicacy of the original forms.
Because the plaster is weaker than the paint layers, I'd like to
remove the outermost layers and retain the more tenacious paint
layers, which actually protect the plaster.  I've tested methods for
removing all layers and for removing only the outmost layers without
finding a satisfactory result.  Chemical pastes soften the plaster
(Prosoco Envirostrip #3 and commercial strippers with methylene
chloride); mechanical methods damage the plaster; steam does not
seem to help.   I'd be very interested in any suggestions.

Catherine Myers
Myers Conservation
Washington, DC

                                  ***
                  Conservation DistList Instance 11:89
                   Distributed: Tuesday, May 5, 1998
                       Message Id: cdl-11-89-015
                                  ***