Oil paintings need to be cleaned every twenty to sixty years.
Smoke, humidity, gravity, pollution, insects, and many other factors can mitigate the surface of an oil painting. In addition, quite often the paint itself grows dry and brittle.
The painting then needs to be refreshed by using an agent, such as salamander oil, for re-hydration. In almost all cases, the work should be cleaned by a professional who not only understands the surface of the painting but also can assess the strength of the base substance which is often used before painting.
There are several factors that need to be addressed concerning the very construction of the painting.
In the hands of a trained professional, the chances of doing damage during cleaning of the painting are removed.
