Thanks to all replies.
Great link to Peter Doodson’s design notes of the DCC packaging. A great insight and real treasure of info.
As I think about it more, drilling could be problematic: small particles of plastic could/would be floating around the inside of the cassette, resulting in possible damage to the tape, or worse, the all important R/W head !!!
Unlike the old analogue compact-cassette, there are no screws to dismantle the case (at least not in my tapes) to help open and clean out swarf, or to remove the tape reels before drilling.
I’m guessing the DCC cassettes clip together somehow, or worse, glued or ultrasonically welded ? This all poses issues with drilling holes, etc…
I don’t really propose to use DCC as an “archive” of my music…the format is a little too rare now. I’m just interested to record some stuff and prove to myself that it works as an interesting recording format, but I don’t want to butcher a tape or risk damage to the machine in the process.
Perhaps @Max is right: Maybe I’ll sell 4 or 5 of my tapes and buy a couple of blanks to satisfy my interest… The machine (without remote) with 8 tapes set me back AUS$30, so I’m not really out of pocket…