Greetings,
I just subscribed to the museum list yesterday and am eagar to find out
what it's all about. To get things rolling, can anyone give me a simple
explanation on the effects of the solvents AB57 and B72 on
frescos?  What chemical reactions occur when the solvent and fresco
interact?  Are these reactions easily controlled?  If so how is the
reaction stopped?  Are these solvents necessarily abrasive and
potentially damaging to the surface of the fresco?  Finally are there
other solvents which could have been used to clean the ceiling?
 
Obviously, my background in chemistry and restoration practices is
limited but any and all replies are greatly appreciated.
 
Diana Vasquez