Italian authorities have decided to clean to Michelangelo's David sculpture with distilled water, despite international objections.
Cleaning the statue has divided the art restoration world
A row had erupted over whether to use water or a dry cleaning process to remove the worst grime from the masterpiece.
Critics said using water on the statue would make its surface too uniform and hide the marble's colours, and destroy the effects nearly 500 years had created on it.
"It isn't a question of an intervention aimed at making the work 'more beautiful'," said Florence museums director Antonio Paolucci.
The argument over how - or even whether - to clean the statue has taken 11 years.
Work is due to start in September and finish in time for the sculpture's 500th anniversary next year.
"If it is just a case of a simple cleaning which does not go beyond removing dirt, there is no problem," said Enzo Settesoldi, an Italian expert told the newspaper La Stampa on Wednesday.
"But once you begin using compresses impregnated with foreign substances, the basic material can change."
There have also been concerns solvents could be used, damaging the statue.
Experts at Florence's Restoration Institution said that in 1843, Aristodemo Costoli cleaned the surface of David with a solution containing 50% hydrochloric acid, leading to the statue's decorative colours disappearing.
A petition had been signed by 39 international art experts to stop Florence's Galleria dell'Accademia using their planned wet technique and demanding that an independent commission should decide on the best method.
Restorer Agnese Parronchi, who was employed to carry out the project, resigned in April, saying that only hair brushes should be used to clean David.
More than one million people see the statue every year
The statue was partly what time and grime had made it and that the Academy's preferred technique would make its surface too uniform, hiding the natural colours and veins of the marble, she told the UK's Independent newspaper last week.
Celebrities including Sting and Mel Gibson are considering donating as much as £500,000 to the project, which has been largely funded so far by a Dutch philanthropist.
The sculpture, housed at Florence's Accademia of Florence, receives over one million visitors a year.