It'd be tricky to use against a mage as a weapon... They don't react to it like faeries and energy creatures do. To tamper with a mage's abilities, they have to be in constant contact with it... Being practically surrounded by it increases the effects.

So unless you wanna try and get a cult mage to hold still long enough for you to wrap him up in iron beads, the standard tactics we know and love are still your best bet...

I think I have heard of a method used to restrain Witches, that involved Iron bindings on their hands, feet, and a nasty contraption around their head.
It was used by the Church during some of their less enlightened times, and rumored to still be used by some unoffical branches of the Roman Chatholic Church these days.
That is the rumor I don't know how valid it is.