I have a CD‑R that I have burned some data onto. I know that the consumed storage space cannot be recovered, but is there some way to delete the data so it can't be (easily) recovered from the disk? Not just deleting filesystem entries, but actually burning out the data? My understanding of the way CD‑ROMs works is that the data is physically recorded by etching the bit pattern into a substrate layer in a way that changes the reflective properties of that layer, so one could erase the data by etching the remaining unetched bits. Could this be done, and if so, is there an existing program for accomplishing this?
CD-R is a one time use device. Once the session is closed, there is no way to append or otherwise alter the data image on the disk (to my knowledge).
With a CD-RW, this would be possible my using some type of "format" command.
Unfortunately, the only way to dispose of the data on a CD-R disk is to destroy the media itself.