One of the miniature paintings we came across last month was showing some signs of biological degradation, but no active microbes were visible on the surface. This was unlike other miniature paintings of the same lot, which had visible mold on surface, specially at the back of the painting. This painting had no mold visible even at the back. But, at a closer look and careful inspection, i realized that there was heavy growth of fungus between the layers of paper. Miniatures are usually made on wasli which is created by adhering many thin layers of paper to make a thick(er) paper support for a painting.
So, the last layer of paper at the back was carefully removed to expose the heavily populated fungal colonies, which were then removed.