The subsequent step is cleaning, removing all accretions on the paint layer equivalent to dust, ingrained dirt, oily or sooty deposits, chook or bat droppings, and many others. That we find in ancient monuments, trying to convey back the colors to their unique brightness as much as possible. Whereas the coating instantly brightened the paint surface, the Shellac progressively underwent oxidation due to reaction with the ambiance. It turned yellow and even brownish,
