Nature painted them. The white one had been exposed to the elements for at least several years. It delaminated. When I found it the decorative design was coming off in sections. The three others I found over the years after the turtles had drown in a creek that runs thru my property. I simply sat them near some large ant hills also on my property and the ants defleshed them over the course of a summer. I then cleaned and polyurethaned them with several coats. According to my Grandad this was a popular activity when he was a young man(1910). I've seen them occasionally for sale on eBay.