Curie's notebooks still carry a trace.

Here's the strange part.

The Curies' laboratory work left a physical trace in some of their notebooks. Radioactive particles from experimental materials became embedded in paper and covers. But radioactive does not mean visibly glowing, and exposure depends on the circumstances. Measurements around a museum display reported very low exposure outside the case. The history is remarkable without adding a science-fiction glow. (Bibliothèque nationale de France)

Go straight to the receipts.

Curious about the methods, dates or details? Open the original source and keep the caveat in view.