Art restorers in Florence, Italy, have begun work on cleaning Michelangelo's David - though critics still believe the work could damage the statue.
The statue celebrates 500 years in 2004
The 499-year-old sculpture is covered with a layer of grime and dust curators want to remove.
Opponents say the decision to use cellulose and water may cause major damage to the masterpiece.
"We're using the most harmless substance possible, water," said Antonio Paolucci, the project's head.
Mr Paolucci said that in 2004 "David' will be 500 years old. We want him to show up for his birthday in the best possible condition."
Restorer Agnese Parronchi left the project earlier this year after several top figures in Italy's art restoration world said she would damage the statue if she used chamois cloths, soft brushes and an eraser to remove the dirt.
Franca Falletti, the director of the Galleria dell'Accademia where David is housed, was among those urging the use of the cleansing pack, using pulped cellulose, rice paper and distilled water.
Tests on a small area of the statue have satisfied local art authorities, and now chief restorer Cinzia Parnigoni will be in charge of the project.
"On David's surface there's a remarkable layer of dirt, especially dust and chalk, which can only be removed through this method," she told the BBC. "Simple mechanical cleaning is not enough."
The gallery has said the restoration work will be carried out in full view of the public.
Distilled water will be used to clean the masterpiece
But critics of the plan, including Columbia University professor James Beck, have called on Italy's culture minister to bring an immediate halt to the restoration.
"We fear that in order to make the statue prettier to look at and prettier for the cameras they will cause the deterioration of the structure and texture of the statue," art expert Giovanni Buti told the BBC.
Restorers will also use mineral spirits to get rid of wax on the statue, which has further alarmed critics.
"It is an unnecessary, unproven intervention," Mr Beck said.