Encaustic painting is a painting medium using melted wax paints and one of the world's oldest form of paint. It was done by the artists of the Ancient Greece. Encaustic came from the Greek word "enkaustikos" which means "to burn in".
Artists of the Middle ages chose other painting mediums, like tempera, oil or fresco because it didn't require the task of building charcoal fires to melt the wax paint. These painting mediums are less of a hassle to use than the encaustic painting medium is.
My opinion of what a literary detective would search is mostly classic things like Beethoven or something that would interest someone for something that happened long ago.