Back to the analog domain, inSync reader, DJ asks:

"I have many used and partially used cassettes (Maxell XL II, TDK SA). I'm thinking of erasing them with a magnetic eraser we use at work for dictation tapes. You just slide the tape through the magnet to erase. Will this work? Will it effect the quality of the tape/ bias etc?"

That is probably going to work as well as anything, but bulk erased tapes never perform up to the quality they did when new. There isn't much you can do about that. You may be able to find a higher quality bulk eraser, which will improve things, but they'll never perform quite like new again. Personally, I have never bothered to erase tapes. I either record over them, which usually erases them well enough (assuming my tape deck is aligned properly). Or if I just want to get rid of the material, I throw them out. The bottom line is that the more you use an analog tape, the worse it gets. This is one of those times I have to say, "Thank goodness for digital!"