How are thousands of years of calligraphy works preserved?

When the ancients moved, they would put their calligraphy works in an environment with suitable temperature and humidity and ventilation. Take it out for a long time to dry, and avoid direct sunlight when drying. Secondly, people should pay great attention to appreciate the works, and they will not touch them directly with their hands, so as to avoid the sweat on their hands directly touching the paintings and calligraphy, causing corrosion, so they are carefully preserved.