<Keep in mind that sources I trust have pointed out that the media between t
<tk50 and tk70 cartridges are different. The tk50 media may not work reliabl
<for long-term storage in a tk70 drive.

I"ve not used TK50 for TK70 as I don't have the TK70.  I have erased carts 
too reuse when they were loaded with junk or mis-inited.

My favorite tool is a DEmagnetizer from RS I bought about 10 years ago and 
is designed for VCR tapes.  You need a really strong field to completely 
wipe a wad of tape 1/2 or 3/4" thick and this one does it.

Procedure is to turn it on at arms length from the media, while mocing it in 
a circular pattern bring it in contact with the tape still moving and then 
repeat on other side for best results.  Then with the juice still on back it 
away to about 2+ feet before turning it off.  

This has worked well for TK50 used on tk50 (and Umatic tapes too!).

Allison