The cleaning of works of art is one of the most complex irreversible processes in restoration. It is necessary to clean varnishes, glues and dirt without removing the paint nor the support of the work.
Since a long time ago, two different processes have been used: the mechanical process and the wet one. When the wet technique used to be employed, a flour and water paste was used, but the humidity could not be controlled, so it could affect the support of the printed layer or work, especially in plaster sculptures. Today, after a new technique has been studied and tested in leading restoration departments and centers around the world, a system based on agarose and agar has been suggested.
When using the new system, the professional could regulate the amount of humidity by making a rigid gel consisting of water and agar or agarose. This gel is spread directly on the surface of the work to be cleaned or on a porous piece of paper. Once it has been spread, it functions as a “molecular sponge” that absorbs any water-soluble material from surfaces.
In addition, its limited adhesion power means that, in general, washing or post-treatment is not necessary after use, as it is the case with other gelling agents. Many benefits are gained from the use of agar: it is thermo-reversible, economical, non-toxic and easy to prepare.
There are many paintings and sculptures that, thanks to the properties of agar, let us enjoy their original image. Some of them are paintings from the Thyssen-Bornemisza Museum or the plaster sculptures that belong to the collection of the Galleria d’Arte di Milano.