Ten minutes sounds about the right length of time for the first traversal of the tape, at which time the collected sticky crud from most old tapes is deposited at the end of the track when it reverses direction, and then proceeds to stick the tape to the head. I don't know if the formulation of the tapes is such that you can remove the stickiness with heat/dehydration. This is also something I need to try on DC-300 carts that have become sticky. You also need to THOUROUGHLY clean the head stack. I have a TZ30 that I leave partially disasembled so I can pull the stack out the top so it can be cleaned with isopropyl on a cotton swab. -- It's probably time to put together lists of what TK50s (distr at least..) have already been read to save others the grief of dealing with old sticky media.