Vittoriano
In the next stage of cleaning, restorers work on the dark deposits, called carbonates: thus, ammonium carbonate compresses are applied to the marble surfaces using paper pulp as a carrier.
The compresses are applied directly to the surface and then covered with aluminum foil to prevent the water from evaporating too quickly due to the heat.
On thinner carbonate deposits, restorers proceed instead with the brush application of dark-colored ion exchange resins.
