They scraped the wall clean to expose lighter stone
Before drawing, many Chauvet panels were prepared by scraping away the surface layer of clay, dirt, and mineral crust. This revealed a **smoother, noticeably paler patch of limestone** that gave the dark charcoal figures stronger contrast and helped them catch the flickering firelight. Clearing the grime also stripped away mold and debris, which helped the paintings survive for tens of thousands of years.
