Originally Posted by
Burton
Normally a plasma torch is used to cut it.
http://www.youtube.com/watch?v=VC3hFr8p2ck
Not sure if any of those are manganese steel, but the first one shown is an Abus 10mm hexagonal, and the last is the Kryptonite Fahgettaboutit (16mm, round, "hardened") which has a Kryptonite rating of "10".