The cleaning of paintings with saliva

Cleaning old paintings is not difficult in most cases. You just need to follow a few simple rules. However, be careful because it’s not always that straightforward.
Have you ever heard of certain magic recipes for cleaning paintings involving milk, raw sliced potatoes, onions, or other oddities? Well, forget them. Each of these materials would leave undesirable residues on the painting. A similarly empirical, but scientifically more accurate system, consists, according to restorer Helmut Ruhemann, author of the book “The Cleaning of Paintings,” in the use of saliva.
This does not mean licking the entire painting, clarifies Paul Frederick in his manual “The Framer’s Answer Book”; cleaning huge paintings, such as Rembrandt's “The Night Watch,” would require years of work! Instead, the saliva should be collected in a container (don’t hesitate to enlist the help of family and colleagues: a spit doesn’t cost anything) and then applied with a brush to the painting. The alternative is to spit directly onto the canvas and then spread the saliva with a brush or a cotton ball. But probably both Ruhemann and Frederick enjoy the paradox and provocation. We will proceed with more orthodox and more hygienic methods, for example...

To be continued in the next episode.