DLT III tapes (TK85-K) and sticky-shed

I've seen plenty of complaints (here and elsewhere) about TK50 cartridges being very difficult to read these days. I'm trying to read TK85-K (DLT III) cartridges and I'm experiencing problems. I've had tapes ripped (although I've found that data elsewhere). So now I'm being particularly careful. If the drive asks for a cleaning tape, I run through a cleaning cycle until it is happy and then I try to load the tape again. However, by the time I've mounted the tape, the drive "Cleaning Required" light is on again. This happens repeatedly, I run a cleaning pass or two and then I get a green light. I might even get as far as loading the tape without and issue, but by the time the tape is mounted, the "Cleaning Required" light is on. So is this likely to be sticky shed? Is the DLT III formulation known to have the same issues? Does baking help? (Not that I'm set up to do that, but I'm in no rush ...) I suppose that it is possible that my cleaning tape is worn out and now past its sell by date. Has anyone cleaned a TZ87 or TZ88 head successfully? It doesn't seem to be terribly accessible, and I'm not sure what I can dismantle without wrecking the alignment. Anyone got any useful suggestions? Antonio -- Antonio Carlini antonio at acarlini.com