A magnetic tape bulk eraser works very well for this. These can be had for not much money these days - most broadcasters are dumping anything to do with magnetic tape. eBay is a good place to look, as are any local radio and TV broadcast facilities. FWIW - the local broadcast engineers are great people to get to know. I have at least 2 units - one from Nortronics and another from Hammond. The Hammond table-top units (foot-switch controlled) are just fabulous - that's what we used to use when erasing carts prior to recording new material onto them. Proper technique is really important: turn the demanetiser on, bring the tool close in and touching, then slowly start moving the tool in a circular motion. Slowly make the circles wider as you are moving the tool further away from the demagnetiser. You can turn the demagnetiser off when the tool is about a full arms-length away from it. Total demagnetising time takes 10 - 15 seconds if you do it properly. dwayne At 12:56 AM 4/3/2008, Forrest Christian wrote: >2) How about some of the commerical "active" demagetizers. Seems like >there are a few that are around $100 or so, but I don't want to buy 2-3 >to find one which works. -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist