It turns out Da Vinci liked playing with chemicals.
https://metro.co.uk/2023/10/17/the-mona-lisa-has-been-hiding-a-toxic-secret-19675327/?utm_source=dlvr.it&utm_medium=blogger
https://metro.co.uk/2023/10/17/the-mona-lisa-has-been-hiding-a-toxic-secret-19675327/?utm_source=dlvr.it&utm_medium=blogger