This is only tangential (I don't think the TSA is doing this), but this is similar to a fascinating technique for finding writing on discarded paper used as fil

This is only tangential (I don't think the TSA is doing this), but this is similar to a fascinating technique for finding writing on discarded paper used as filler in bindings and such in old books. https://medievalbooks.nl/2015/12/18/x-rays-expose-a-hidden-medieval-library/ https://medievalbooks.nl/2015/12/18/x-rays-expose-a-hidden-m...