Big Blue Flame.
I wouldn't hit it with anything no no no. That which has been beat cannot be un-beat!
Incidentally, anyone who says they've run a cutting torch but never caught and anything on fire is either a liar or a liar LOL!
With this in mind, I always opt for the least destructive method first.
Well, take a look at what else you might heat. Seals are top of the list for things which get ruined when the BBF comes out to play.
If you go that way (and this is good advice for lots of things) wrap the tender bits in a wet towel.
But I'm not telling a welder anything he doesnt already know am I?