After 2,000 years, the two faces of the ancient Greek god, Heros, have had cosmetic surgery, but with nary a nip or tuck. Acid, tweezers and a toothbrush did the job. Those faces decorate the Amorini Balsamary, an ancient perfume bottle that was among 20 pieces of Roman Empire glassware recently restored through a special process for the Giovanni F. Mariani Glass Museum at Castello Banfi, Montalcino, Tuscany. According to Marion Pries, the museum's curator, the work was done over a six-week period at a laboratory in San Giovanni Valdarno, a small Tuscan city near Florence renowned for glass making. The project was directed by Silvia Vilucchi of the Siena province's office of arts and monuments, who authored a recently released book on the history of glass, its production and its restoration, entitled "Vitrum - La Materia, Il Degrado, Il Restauro," and prominently featuring the Banfi museum. She was assisted in the restoration project by ten students with academic backgrounds in fine arts, archeology or history, all pursuing glass conservation as a career. Ms. Pries says that much of the cleaning process is known only to the master restorer but soap and water don't figure into it. A microscope is used to determine what sort of treatment is required and then is employed to check every step of the process. She explained that the vessel's interior and exterior are first encased in cotton on to which small amounts of an acid solution are poured. When the solution loosens or dissolves dirt and patina, the vessel's surface is gently cleaned with a small pair of tweezers or a toothbrush. It takes several hours of patient scratching before the vessel regains its original splendor. Cost of their restoration: zip. "It was a labor of love," Ms. Pries observes. From June 3 to July 9, the 20 restored pieces were publicly displayed in San Giovanni Valdarno. In addition to the Amorini balsamary, there will be drinking glasses, small amphorae, jugs, bottles, flasks, plates, ash urns and other balsamaries that date from the first through the fifth centuries A.D. The Giovanni F. Mariani Glass Museum, established in 1992, retraces glassmaking from ancient Egyptian times to the present day. It occupies five rooms in the west wing of the 13th century castle that overlooks Castello Banfi's vineyard estate.