Thanks very much for answers/replies!

One thing confirmed, I will have to cut them out, even if I was going to re-build them, I think the ones in there, are un-recoverable. They are in the open (I mean not restricting the exhaust position), so that's good. If the new parts are going to be very pricey, I will decide on cutting them away. Here in Australia, it gets cold in places, but not that cold!