One of my friends posted this on FaceBook:
and it got me wondering if Magneto's power over metal was strong enough to lift/control Mjolnir.
Science Fiction & Fantasy Stack Exchange is a question and answer site for science fiction and fantasy enthusiasts. It only takes a minute to sign up.Sign up to join this community
The worthiness clause might not stop Magneto from deflecting the thrown hammer, because it can be done (and has been done), but he should not be able to grab or hold the hammer physically and prevent it from returning to Thor. He has been able to create a barrier which keeps the weapon from immediately returning to Thor (see below). He certainly should not be allowed to hit Thor with it, in effect using it as a weapon.
He can and has pushed Mjolnir away using its metallic nature against it. This is still not truly wielding it, just moving it around by manipulating a magnetic field.
The recent exception with the Red Hulk beating Thor with his hammer in zero gravity has left the comic fans very, very unhappy. (As it should.)
I have one more Journey into Mystery image to show where Thor, using Mjolnir absorbs Magneto's magnetic field into itself and dispels it so that Thor can bring the pain to Magneto. Enjoy.
In the cinematic universe, where everything Asgard is really advanced technology instead of magic, there does exist a possibility that Magneto can "wield" it regardless of how worthy he is:
The current top answer to Can Thor's hammer be wielded by anyone in outer space? supposes the mechanism behind preventing anyone from wielding Thor's Hammer is quantum levitation - where the hammer "locks" itself into magnetic fields. Since Magneto can manipulate magnetic fields, he would be able to move the hammer no matter where it locked itself into place.