[GeoffB17]

Huh?

You were the one worrying about leaving something watchable. I suppose that time does have some impact. Remember the warnings about leaving tapes (cassettes) near to your speakers. I've always understood that for the odd minute or two this was no problem, but if sitting there for days, then the recording may not be so good any more.

I admitt, I've not tested this. You might? Try the magnet for a few minutes, check the result. If no good, try 30 mins, then 1 hour, etc. The more powerful the magnet, the less time. Moving the magnet about (circular movement) will prob help a LOT more, but if you've got a pile of tapes to do, this will get to be hard work (on the arm).

Blanking a floppy disk takes a few seconds, but a spool of DV tape is much thicker, more dense, and I would guess will take much longer.

Geoff