with non destructive methods such as Computed Tomography (CT) imaging it is possible to investigating and read hidden cuneiform texts without breaking the envelope, also Imaging the interior of cuneiform letters. This method is a sophisticated imaging technique.

http://www.nino-leiden.nl/message/seeing-through-clay-4000-#annotations:OGSbcLpWEeqFh7dLZ30UwA

https://www.youtube.com/watch?v=5RmTpMoH-1o&feature=emb_logo

Computed Tomography scan on a enveloped Cuneiform tablet http://www.nino-leiden.nl/message/prestigious-award-for-scanning-for-syria

https://www.tudelft.nl/en/delft-outlook/articles/cuneiform-in-a-scanner/

https://www.researchgate.net/publication/226355193_The_Use_of_Medical_Computed_Tomography_CT_Imaging_in_the_Study_of_Ceramic_and_Clay_Archaeological_Artifacts_from_the_Ancient_Near_East

Imaging the interior of cuneiform letters by CT scanning.

http://www.nino-leiden.nl/message/seeing-through-clay-4000-year-old-tablets-in-hypermodern-ct-scanner