Wait. ‘Magnet’ plus ‘audio tape’? I’m surprised you kept the job. The last thing in the world that you want is a magnetised razor blade being used for editing tape! Must have have made a lovely thump as the edit passed the heads...
And never in all my many years in recording studios did I ever ever see an engineer or assistant leave a razor blade on top of a reel. Ever.
A ‘budget’ studio I worked in once had a Brenell 1” 8 track machine, this being the cheapest on the market. This meant it lacked some sophistication in the transport department. So you could go directly from fast wind to play without the transport slowing the reels down before engaging the pinch wheel and capstan. This produced what was called a ‘bootlace’, which was a few feet of tape stretched from being 1” wide to about a 1/4”. Needless to say this would always occur somewhere in the middle of a master take.
A full reel of tape on fast wind is a sight (and sound) to behold.