I'm a scrounge. I work with computers. I pull magnets from dead hard drives - they typically have one or two really strong rare earth magnets which are handy for various purposes. I've recently begun to wonder if the sheilds or pole pieces around those magnets (the ones that sit on the back side of the head apparatus to position it) are plain steel, which I've pretty much assumed would be the case (cheap) or if that sheild might just be mu-metal.
If there is either an easy way to tell, or if somone on here knows in general or specific cases from the manufacturing end, I'd like to know.