We spent the morning learning more about the techniques of evaluating and restoring old paintings, using 400 year-old paintings that had been found rolled up in closets, stashed in basements, moldy, creased, torn. It appears to me that the main techniques involve rolling hand-made special Q-tips soaked in solution across the painting, quarter inch by quarter inch. 
My suggestion, “Can’t you just hack off the crummy parts?” went over like a lead balloon with the art historians and the museum curators in our group.
Gigi's Italia 